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12 novembre 2011 6 12 /11 /novembre /2011 03:31

Industrial release and occupational exposure limits

Typical levels of beryllium that industries may release into the air are of the order of 0.01 µg/m3, averaged over a 30-day period, or 2 µg/m3 of workroom air for an 8-hour work shift. Sony VAIO VGN-CR21E/W Battery

Compliance with the current U.S. Occupational Safety and Health Administration (OSHA) permissible exposure limit for beryllium of 2 µg/m3 has been determined to be inadequate to protect workers from developing beryllium sensitization and CBD.Sony VAIO VGN-CR21S/L Battery

The American Conference of Governmental Industrial Hygienists(ACGIH), which is an independent organization of experts in the field of occupational health, has proposed a threshold limit value (TLV) of 0.05 µg/m3 in a 2006 Notice of Intended Change (NIC).Sony VAIO VGN-CR21S/P Battery

This TLV is 40 times lower than the current OSHA permissible exposure limit, reflecting the ACGIH analysis of best available peer-reviewed research data concerning how little airborne beryllium is required to cause sensitization and CBD.Sony VAIO VGN-CR21S/W Battery

Because it can be difficult to control industrial exposures to beryllium, it is advisable to use any methods possible to reduce airborne and surface contamination by beryllium, to minimize the use of beryllium and beryllium-containing alloys whenever possible, and to educate people about the potential hazards if they are likely to encounter beryllium dust or fumes.Sony VAIO VGN-CR21Z/N Battery

On 29 January 2009, the Los Alamos National Laboratory announced it was notifying nearly 2,000 current and former employees and visitors that they may have been exposed to beryllium in the lab and may be at risk of disease. Concern over possible exposure to the material was first raised in November 2008, when a box containing beryllium was received at the laboratory's short-term storage facility.Sony VAIO VGN-CR21Z/R Battery

Although beryllium (Be) has 12 known isotopes, only one of these isotopes (Be) is stable and a primordial nuclide. As such, it is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low.Sony VAIO VGN-CR220E/R Battery

Most 9Be in the universe is thought to be formed by cosmic ray nucleosynthesis from cosmic ray spallation in the period between the Big Bang and the formation of the solar system.

Of the 11 radioisotopes of beryllium, the most stable are 10Be with a half-life of 1.39 million years and 7Be with a half-life of 53.22 days. Sony VAIO VGN-CR23/B Battery

All other radioisotopes have half-lives under 13.85 seconds, most under 20 milliseconds. The least stable isotope is 6Be, with a half-life measured as 92 keV.

Beryllium is unique as being the only monoisotopic element with an even number of protons. It is also the only one with an odd number of neutrons. Sony VAIO VGN-CR23/L Battery

There are 20 other monoisotopic elements (fluorine, sodium, aluminum, phosphorus, scandium, manganese, cobalt, arsenic, yttrium, niobium, rhodium, iodine, cesium, praseodymium, terbium, holmium, thulium, gold, bismuth, and francium) but all have odd atomic numbers, and even numbers of neutrons.Sony VAIO VGN-CR23/N Battery

The natural light-element ratio of equal protons and neutron numbers is prevented in beryllium by the extreme instability of 8
Be toward double-alpha decay, which is favored due to the extremely tight binding of 4
He nuclei. The half-life for the decay of 8
Be is only 6.7(17)×10?17 seconds.

Beryllium is prevented from having a stable isotope with 4 protons and 6 neutrons by the very large mismatch in proton/neutron ratio for such a light element. Nevertheless, this isotope, 10
Be, has a half-life of 1.39 million years, which indicates unusual stability for a light isotope with such a large neutron/proton imbalance.Sony VAIO VGN-CR23/P Battery

Still other possible beryllium isotopes have even more severe mismatches in neutron and proton number, and thus are even less stable.

The isotopes 7
Be, with a half-life of 53 days, and 10
Be are both cosmogenic nuclides because they are made on a recent timescale in the solar system by cosmic ray spallations, like 14
C. Sony VAIO VGN-CR23/R Battery

These two radioisotopes of beryllium in the atmosphere track the sun spot cycle and solar activity, since this affects the magnetic field that shields the Earth from cosmic rays. The rate at which the short-lived 7
Be is transferred from the air to the ground is controlled in part by the weather.Sony VAIO VGN-CR23/W Battery

AlBeMet® is the trade name of the Materion Brush Beryllium & Composites (formerly known as Brush Wellman) company for a beryllium and aluminium composite materialderived by a powder metallurgy process. AlBeMet® is formed by hot consolidating gas atomized prealloyed powder.Sony VAIO VGN-CR240E/B Battery

Each powder particle contains aluminium between beryllium dendrites producing a uniform microstructure. Since beryllium is the second least dense elemental metal, these alloys are significantly less dense than aluminium.

Be-Al alloys are primarily of interest to the aerospace industry, due to the weight advantage they provide. They are currently used in satellites.Sony VAIO VGN-CR240N/B Battery

Due to the high toxicity of beryllium the machining has to be conducted with caution to prevent exposure of the workers.

Basic properties

AlBeMet® has a density of 2.071 g/cm³ (0.07482 lb/in³).

MECHANICAL PROPERTIES The mechanical properties of AM162 have been extensively characterized in all three-product forms. But a significant design database has been developed for the extruded product form.Sony VAIO VGN-CR25G/N Battery

The extruded bar is fabricated by Cold Isostatic Pressing (CIPing) the isotropic spherical aluminum-beryllium powder into semi-dense billets and then canning the billet for subsequent extrusion with a minimum of a 4:1 reduction ratio. Mechanical properties are minimum values at room temperature. Sony VAIO VGN-CR290EAL Battery

Wrought mechanical properties for extrusions are in the longitudinal direction. Transverse properties are generally lower. A number of standard extrusion dies are available. Rolled product is available in a thickness range of 0.063” to 0.313” x 25” (0.16 to 0.795 cm x 63.5 cm) length time’s width dependent on gauge.Sony VAIO VGN-CR290EAN Battery

Mechanical properties for HIP’d, extruded, and/or rolled AlBe metal matrix composites are in the annealed condition.

PHYSICAL PROPERTIES 1. High modulus-to-density ratio, 3.8 times that of aluminum or steel, minimizes flexure and reduces the chance of mechanically induced failure. 2.Sony VAIO VGN-CR290EAP Battery

Thermal conductivity of approximately 210 W/m•K exceeds by about 25% that of common aluminum metal matrix composites such as Al 6061. 3. The CTE of 13.9 ppm/K matches that of the ceramic chip carriers (alumina has CTE of ~8ppm/K) more closely than does aluminum, which has a CTE of 24ppm/K. 4. Sony VAIO VGN-CR290EAR Battery

The stiffness and low density of AlBeMet® are beneficial in aircraft, where high loads generated during tight maneuvering can cause flexure of circuit boards, and subsequent mechanical failure.

FATIGUE PROPERTIES Is Cyclic fatigue critical to the life cycle of your component? Sony VAIO VGN-CR290EAW Battery

The fatigue properties of AlBeMet® extruded material have been tested using the Krause rotating beam fatigue test utilizing fully reversed cycles with a R= +0.1. The fatigue limit, 1 x 10-7 cycles was about 207 MPa (30Ksi) in the longitudinal direction and 165 MPa (25 Ksi) in the transverse direction.Sony VAIO VGN-CR29XN/B Battery

This property is approximately 75% of the minimum RT yield strength, which is two times that of typical fatigue properties of 6061T6 aluminum.

THERMAL PROPERTIES Most important fact in Surface Mount Technology (SMT) circuit board cores is coefficient of thermal expansion (CTE).Sony VAIO VGN-CR305E/RC Battery

The better the CTE match, the less strain imposed on solder joints. Less strain translates into better fatigue life for solder joints and longer life for the board. Thermal management capabilities, characterized by the thermal conductivity and heat capacity, have also been found to be important factors.Sony VAIO VGN-CR31S/D Battery

E-Material, also called E Material, is a metal matrix composite consisting of beryllium matrix with beryllium oxide particles. It has high thermal conductivity(210-230 W/m K), and its thermal expansion can be adjusted to match other materials, e.g. silicon and gallium arsenide chips and various ceramics.Sony VAIO VGN-CR323/W Battery

It is chiefly used in microelectronics as substrate for power semiconductor devices and high density multi-chip modules, where it aids with removal of waste heat. E-materials have low weight and high strength, making them especially suitable for aerospace technology. Their high elastic modulus is favorable for absorbing vibrations and lowering material fatigue of attached modules and wire bonds.Sony VAIO VGN-CR33 Battery

Several variants exist:

  • E-20, containing 80 vol.% of beryllium and 20 vol.% (25.8-32.25 w.%) beryllium oxide. Its thermal conductivity is 210 W/(m·K). Its thermal expansion coefficient is 8.7. Its density at 25 °C is 2.045 g/cm3.
  • E-40, containing 60 vol.% of beryllium and 40 vol.% (49.5-54.8 w.%) beryllium oxide. Its thermal conductivity is 220 W/(m·K). Its thermal expansion coefficient is 7.5. Its density at 25 °C is 2.277 g/cm3. Sony VAIO VGN-CR382 Battery
  • E-60, containing 40 vol.% of beryllium and 60 vol.% (69.4-73.2 w.%) beryllium oxide. Its thermal conductivity is 230 W/(m·K). Its thermal expansion coefficient is 6.1. Its density at 25 °C is 2.513 g/cm3.

E-materials are prepared by impact grinding and then hot isostatic pressing into a block. Sony VAIO VGN-CR490EBL Battery

The block is then sliced to cards, sawn to required shape, polished, machined, and optionally plated with e.g. nickel, cadmium, chrome, silver, copper, or gold. Without coatings, the corrosion resistance of E-materials is similar to aluminium.Sony VAIO VGN-CR490EBN Battery

E-materials are used in aerospace technology, e.g. as laminated multi-chip modules in Iridium and Globalstar satellites, as heat sinks, and in avionics of F-22 Raptor, F-16 Fighting Falcon, F/A-18 Hornet, and the Joint Strike Fighter. It is also used in SEM-E modules and printed wiring boards.Sony VAIO VGN-CR490EBP Battery

Care has to be taken during machining and handling of E-materials, as beryllium and its compounds are toxic.

Gold-tin and gold-germanium alloys can be used for brazing with kovar or CuMo and other electronics packaging alloys.Sony VAIO VGN-CR490EBR Battery

A similar material is Dymalloy, with copper-silver alloy instead of beryllium and diamond instead of beryllium oxide, or AlSiC, aluminium with silicon carbide. Other materials are copper reinforced with carbon fiber, diamond-reinforced aluminium, reinforced carbon-carbon, and pyrolytic graphite.Sony VAIO VGN-CR490EBT Battery

Another similar material is AlBeMet®, a metal-matrix composite of aluminium and beryllium.

Glucydur is the trade name of a metal alloy with a low coefficient of thermal expansion, used for making balance wheels and other parts of mechanical watches.Sony VAIO VGN-CR490EBW Battery

Glucydur is a beryllium bronze; an alloy of beryllium, copper and iron. In addition to its low coefficient of thermal expansion, its hardness (400 Brinell), nonmagnetizability, and resistance to deformation and damage make it suited for making precision parts that must have high dimensional stability. Glucydur is also resistant to corrosion; it is rather inert chemically.Sony VAIO VGN-CR50B/W Battery

Glucydur was developed about the same time with another non-magnetic material, Nivarox.

Basic beryllium acetate is the chemical compound with the formula Be4O(O2CCH3)6. Although this compound has no applications and has been only lightly studied, it adopts a distinctive structure.Sony VAIO VGN-CR51B/W Battery

"Basic acetates" consist of an ensemble of metal atoms, a central oxide atom, and an exterior of acetate groups. Another family of basic acetates are trimetallic with the formula M3O(O2CCH3)6(H2O)3 (M = Cr, Fe, Ru). Mixed metal members of this family also exist.

Beryllide is an intermetallic compound of beryllium with other metals, e.g. zirconium, tantalum, titanium, nickel, or cobalt.Sony VAIO VGN-CR520E/J Battery

Beryllides of cobalt and nickel have metallurgical importance as the precipitated phase in beryllium copper alloys.

In nuclear technology, beryllides are investigated as neutron multipliers.

Iron beryllide (FeBe5) fibers in iron aluminide matrix are investigated as a composite material.Sony VAIO VGN-CR52B/W Battery

Beryllium carbonate is a chemical compound with the chemical formula BeCO3. There are three forms reported, anhydrous, a tetrahydrate and basic beryllium carbonate. The anhydrous form is reported to be unstable, decomposing to BeO and carbon dioxide, and requiring storage under CO2.Sony VAIO VGN-CR590EBL Battery

The tetrahydrate is said to be formed when CO2 is bubbled through a solution of Be(OH)2 and is also reported to be similarly unstable. Basic beryllium carbonate is a mixed salt, which can be prepared by the reaction of beryllium sulfate and ammonium carbonate, and contains both carbonate and hydroxide ions, with formula Be2CO3(OH)2.Sony VAIO VGN-CR590EBN Battery

It is believed that in the older literature this is probably what was referred to as beryllium carbonate.

The structure of solid BeF2 resembles that for silicon dioxide. Be2+ centers are four coordinate and tetrahedral. Sony VAIO VGN-CR590EBP Battery

Solid BeF2 adopts a number of polymeric structures analogous to those adopted by SiO2 namely ?-quartz, ?-quartz, crystobalite andtridymite, and its reactions with fluorides are quite analogous to the reactions of SiO2 with oxides. An analogy exists between BeF2 and AlF3: both adopt extended structures at mild temperature. BeF2 is considered to be highly covalent.Sony VAIO VGN-CR590EBR Battery

Gaseous BeF2 is found in the gas-phase above 1160 °C. Like the isoelectronic gases CO2 and SiO2, it is a linear molecule. The Be-F distance of 177 pm.[4] The difference between the ambient temperature structures of BeF2 (rock-like solid) and CO2 (gas) reflects the low tendency of alkali metals to form multiple bonds.Sony VAIO VGN-CR590EBT Battery

Molten BeF2 resembles water in some ways, since it is a triatomic molecule with strong interactions via Be—F—Be bonds. As in water, the density of BeF2 decreases near its melting point. Liquid (molten) beryllium fluoride also has a fluctuating tetrahedral structure.Sony VAIO VGN-CR590EBW Battery

Beryllonite is a rare sodium beryllium phosphate mineral with formula NaBePO4. The tabular to prismatic monoclinic crystals vary from colorless to white or pale yellowish, and are transparent with a vitreous lustre. Twinning is common and occurs in several forms. It exhibits perfect cleavage in one direction. Sony VAIO VGN-CR60B/L Battery

The hardness is 5.5 to 6 and the specific gravity is 2.8.Refractive indices are n? = 1.552, n? = 1.558 and n? = 1.561. A few crystals have been cut and faceted, but, as the refractive index is no higher than that of quartz, they do not make very brilliant gemstones.Sony VAIO VGN-CR60B/P Battery

It occurs as a secondary beryllium mineral in granitic and alkalic pegmatites. It was first described from complex crystals and as broken fragments in the disintegrated material of a granitic vein at Stoneham, Oxford County, Maine where it is associated with feldspar, smoky quartz, beryl and columbite. Sony VAIO VGN-CR60B/R Battery

It was discovered by James Dwight Dana in 1888, and named beryllonite for its beryllium content.

Bromellite, whose name derives from the Swedish chemist Magnus von Bromell (1670–1731), is a white oxide mineral, found in complex pegmatitic manganese-iron deposits, but is more frequently made synthetically. This is a rare mineral to encounter in its natural state, but it has been made synthetically for over 40 years.Sony VAIO VGN-CR61B/L Battery

Uses of bromellite

Bromellite, as a beryllium-containing mineral, has some uses. Industrially, natural specimens have the potential to be an ore of beryllium. It is one of the reagents that can be used in the manufacture of artificial emeralds. As an additive, bromellite confers high mechanical strength and very high thermal conductivity. Sony VAIO VGN-CR61B/N Battery

In nuclear reactors, it is used as amoderator for fast neutrons. Ceramics containing bromellite are used in electronics, as well as crucibles for the melting ofuranium and thorium. Bromellite, both natural and synthetic, is also used as a gemstone or as a collector's mineral.Sony VAIO VGN-CR61B/P Battery

As agemstone bromellite is extremely rare. To date there has been found only one crystal that is large enough to be cut. In 2000 Dunil Palitha Gunasekara of Ratnapura, Sri Lanka purchased a rough colorless 17.77-ct crystal from Ratnapura. He cut it into 15 pieces, of which 3 pieces with 2.80, 1.92 and 0.68 ct were sent to the GIA laboratory for further testing since he thought them to be Johachiodolite at first. Sony VAIO VGN-CR61B/R Battery

These gemstones are the first reported examples of faceted gem-quality Bromellite.

Euclase is a beryllium aluminium hydroxide silicate mineral (BeAlSiO4(OH)). It crystallizes in the monoclinic crystal systemand is typically massive to fibrous as well as in slender prismatic crystals. It is related to beryl (Be3Al2Si6O18) and other beryllium minerals. It is a product of the decomposition of beryl in pegmatites.Sony VAIO VGN-CR62B/L Battery

Euclase crystals are noted for their blue color, ranging from very pale to dark blue. The mineral may also be colorless, white, or light green. Cleavage is perfect, parallel to the clinopinacoid, and this suggested to René Just Haüy the name euclase, from the Greek ??, easily, and ??????, fracture. Sony VAIO VGN-CR62B/N Battery

The ready cleavage renders the stone fragile with a tendency to chip, and thus detracts from its use for personal ornament. When cut it resembles certain kinds of beryl and topaz, from which it may be distinguished by its specific gravity (3.1). Its hardness (7.5) is rather less than that of topaz.Sony VAIO VGN-CR62B/P Battery

It was first reported in 1792 from the Orenburg district in the southern Urals, Russia, where it is found with topaz andchrysoberyl in the gold-bearing gravels of the Sanarka. Its type locality is Ouro Prêto, Minas Gerais, Southeast Region,Brazil, where it occurs with topaz. It is met with as a rarity in the mica-schist of the Rauris in the Austrian Alps.Sony VAIO VGN-CR62B/R Battery

Gadolinite is a silicate mineral which consists principally of the silicates of cerium, lanthanum, neodymium, yttrium,beryllium, and iron with the formula (Ce,La,Nd,Y)2FeBe2Si2O10. It is called gadolinite-(Ce) or gadolinite-(Y) depending on the prominence of the variable element composition (namely, Y if it has more yttrium, and Ce if it has more cerium). Sony VAIO VGN-CR70B/W Battery

It may contain 35.48% yttria sub-group rare earths, 2.17% ceria earths, up to 11.6% BeO and traces of thorium. It is found in Sweden, Norway, and the USA (Texas and Colorado).

Characteristics

Gadolinite is fairly rare and typically occurs as well-formed crystals. It is nearly black in color and has a vitreousluster. Sony VAIO VGN-CR71B/W Battery

Its hardness is between 6.5 and 7, and its specific gravity is between 4.0 and 4.7. It fractures in a conchoidalpattern. The mineral's streak is grayish-green. It is also pyrognomic, which means that it becomes incandescent at a relatively low temperature.Sony VAIO VGN-CR72B/W Battery

Name and discovery

Gadolinite was named in 1800 for Johan Gadolin, the Finnish mineralogist-chemist who first isolated an oxide of the rare earth element yttrium from the mineral in 1792. The rare earth gadolinium was also named for him. However, gadolinite does not contain more than trace amounts of gadolinium.Sony VAIO VGN-CR90HS Battery

When Gadolin analyzed this mineral, he missed an opportunity to discover a second element: what he thought was aluminium (alumina) was in fact an element that would not be officially discovered until 1798: beryllium (beryllia).

Pezzottaite, marketed under the name raspberyl or raspberry beryl, is a newly identified mineral species, first recognized by the International Mineralogical Association in September 2003. Sony VAIO VGN-CR90NS Battery

Pezzottaite is a caesium analogue of beryl, asilicate of caesium, beryllium, lithium and aluminium, with the chemical formula Cs(Be2Li)Al2Si6O18. Named after Italiangeologist and mineralogist Federico Pezzotta, pezzottaite was first thought to be either red beryl or a new variety of beryl ("caesium beryl");Sony VAIO VGN-CR90S Battery

unlike other beryls, however, pezzottaite contains lithium and crystallizes in the trigonal crystal system rather than the hexagonal system.

Colours include shades of raspberry red to orange-red and pink. Recovered from miarolitic cavities in the granitic pegmatitefields of Fianarantsoa province, southern Madagascar,Sony VAIO VGN-CR92HS Battery

the pezzottaite crystals were small—no more than about 7 cm in their widest dimension—and tabular or equant in habit, and few in number, most being heavily included with growth tubes and liquid feathers. Approximately 10 per cent of the rough material would also exhibit chatoyancy when polished. Most cut pezzottaite gems are under one carat (200 mg) in weight and rarely exceed two carats (400 mg).Sony VAIO VGN-CR92NS Battery

With the exception of hardness (8 on Mohs scale), the physical and optical properties of pezzottaite—i.e., specific gravity3.10 (average), refractive index 1.601 to 1.620, birefringence 0.008 to 0.011 (uniaxial negative)—are all higher than typical beryl. Pezzottiate is brittle with a conchoidal to irregular fracture, and streaks white. Sony VAIO VGN-CR92S Battery

Like beryl, it has an imperfect to fair basal cleavage. Pleochroism is moderate, from pink-orange or purplish pink to pinkish purple. Pezzottaite's absorption spectrum, as seen by a hand-held (direct vision) spectroscope, features a band at 485–500 nm with some specimens showing additional weak lines at 465 and 477 nm and a weak band at 550 to 580 nm.Sony VAIO VGN-CS118E/Q Battery

Most (if not all) of the Madagascan deposits have since been exhausted. Pezzottaite has been found in at least one other locality, Afghanistan: this material was first thought to be caesium-rich morganite (pink beryl). Like morganite and bixbite, pezzottaite is believed to owe its colour to radiation-induced colour centres involving trivalent manganese. Sony VAIO VGN-CS118E/R Battery

Pezzottaite will lose its colour if heated to 450°C for two hours, but the colour can be restored with gamma irradiation.

Phenakite or phenacite is a fairly rare nesosilicate mineral consisting of beryllium orthosilicate, Be2SiO4. Occasionally used as a gemstone, phenakite occurs as isolated crystals, which are rhombohedral with parallel-faced hemihedrism, and are either lenticular or prismatic in habit:Sony VAIO VGN-CS118E/W Battery

the lenticular habit is determined by the development of faces of several obtuse rhombohedra and the absence of prism faces. There is no cleavage, and the fracture is conchoidal. The Mohs hardness is high, being 7.5 - 8; the specific gravity is 2.96. The crystals are sometimes perfectly colorless and transparent, but more often they are greyish or yellowish and only translucent; Sony VAIO VGN-CS11S/P Battery

occasionally they are pale rose-red. In general appearance the mineral is not unlike quartz, for which indeed it has been mistaken.

Occurrence

Phenakite is found in high-temperature pegmatite veins and in mica-schists associated with quartz, chrysoberyl, apatite and topaz.Sony VAIO VGN-CS11S/Q Battery

It has long been known from the emerald and chrysoberyl mine on the Takovaya stream, near Yekaterinburg in the Urals of Russia, where large crystals occur in mica-schist. It is also found with topaz and amazon-stone in the granite of the Ilmen Mountains in the southern Urals and of the Pikes Peak region in Colorado (USA). Sony VAIO VGN-CS11S/W Battery

Large crystals of prismatic habit have been found in a feldspar quarry at Kragero in Norway. Framont near Schirmeck in Alsace is another well-known locality. Still larger crystals, measuring 1 to 2 in. in diameter and weighing 28 lb (13 kg). have been found at Greenwood in Maine, but these are pseudomorphs of quartz after phenakite.Sony VAIO VGN-CS11Z/R Battery

For gem purposes the stone is cut in the brilliant form, of which there are two fine examples, weighing 34 and 43 carats (6.8 and 8.6 g), in the British Museum. The indices of refraction are higher than those of quartz, beryl or topaz; a faceted phenakite is consequently rather brilliant and may sometimes be mistaken for diamond.Sony VAIO VGN-CS120J/P Battery

Tugtupite is a rare beryllium aluminium tectosilicate. It also contains sodium and chlorine and has the formulaNa4AlBeSi4O12Cl. Tugtupite is a member of the silica deficient feldspathoid mineral group. It occurs in high alkali intrusiveigneous rocks.

Tugtupite is tenebrescent, sharing much of its crystal structure with sodalite, and the two minerals are occasionally found together in the same sample.Sony VAIO VGN-CS120J/Q Battery

Tugtupite occurs as vitreous, transparent to translucent masses of tetragonal crystals and is commonly found in white, pink, to crimson, and even blue and green. It has a Mohs hardness of 4 and a specific gravity of 2.36. Tugtupite is also a non-radioactivesubstance. It fluoresces crimson under ultraviolet radiation.Sony VAIO VGN-CS120J/R Battery

It was first found in 1962 at Tugtup agtakôrfia Ilimaussaq intrusive complex of southwest Greenland. It has also been found atMont-Saint-Hilaire in Quebec and in the Lovozero Massif of the Kola Peninsula in Russia

The name is derived from the Greenlandic Inuit word for reindeer (tuttu), and means "reindeer blood."Sony VAIO VGN-CS190JTB Battery

The U.S. Geological Survey reports that in Nepal, tugtupite (as well as jasper and nephrite) were found extensively in most of the rivers from the Bardia to the Dang.

Emerald is a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium and sometimesvanadium.Sony VAIO VGN-CS190JTP Battery

Beryl has a hardness of 7.5–8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highlyincluded, so their toughness (resistance to breakage) is classified as generally poor.

Etymology

The word "Emerald" is derived (via Old French: Esmeraude and Middle English: Emeraude), from Vulgar Latin: Esmaralda/Esmaraldus, a variant of Latin Smaragdus, which originated in Greek: ????????? (smaragdos; "green gem");Sony VAIO VGN-CS190JTQ Battery

its original source being either the Hebrew word ?????? izmargad meaning "emerald" or "green" or the Sanskrit word ??????? marakata meaning "green." The name could also be related to the Semitic word baraq (?????? ;???????; "lightning" or "shine") (cf.Hebrew: ???? bareqeth and Arabic: ??? barq "lightning"). Sony VAIO VGN-CS190JTR Battery

It is the same source for the names Persian (????? zomorrod), Turkish(zümrüt), Sanskrit (??????? maragdam), Telugu (Paccha), Georgian (????????; zurmukhti), Russian (???????; izumrud) and Armenian zmruxt.

Properties determining value

Emeralds, like all colored gemstones, are graded using four basic parameters – the four Cs of Connoisseurship: Color, Cut, Clarityand Crystal. Sony VAIO VGN-CS190JTW Battery

The last C, crystal is simply used as a synonym that begins with C for transparency or what gemologists call diaphaneity. Before the 20th century, jewelers used the term water as in "a gem of the finest water"  to express the combination of two qualities, color and crystal. Normally, in the grading of colored gemstones, color is by far the most important criterion. Sony VAIO VGN-CS190NAB Battery

However, in the grading of emerald, crystal is considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue as described below, but also a high degree oftransparency to be considered a top gem.

In the 1960s the American jewelry industry changed the definition of 'emerald' to include the green vanadium-bearing beryl as emerald.Sony VAIO VGN-CS190NAC Battery

As a result, vanadium emeralds purchased as emeralds in the United States are not recognized as such in the UK and Europe. In America, the distinction between traditional emeralds and the new vanadium kind is often reflected in the use of terms such as 'Colombian Emerald.' Sony VAIO VGN-CS190NAD Battery

Color

Scientifically speaking, color is divided into three components: hue, saturation and tone. Yellow, blue and red the hues found adjacent to green on the spectral color wheel, are the normal secondary hues found in emerald.Sony VAIO VGN-CS190NBB Battery

Emeralds occur in hues ranging from yellow-green to blue-green. The primary hue must, of course, be green. Only gems that are medium to dark in tone are considered emerald. Light-toned gems are known by the species name, green beryl. In addition, the hue must be bright (vivid).Sony VAIO VGN-CS190NCA Battery

Gray is the normal saturation modifier or mask found in emerald. A grayish green hue is a dull green.

Clarity

Emerald tends to have numerous inclusions and surface breaking fissures. Unlike diamond, where the loupe standard, i.e. 10X magnification, is used to grade clarity, emerald is graded by eye. Sony VAIO VGN-CS190NCB Battery

Thus, if an emerald has no visible inclusions to the eye (assuming normal visual acuity) it is considered flawless. Stones that lack surface breaking fissures are extremely rare and therefore almost all emeralds are treated, "oiled", to enhance the apparent clarity.Sony VAIO VGN-CS190NCC Battery

Eye-clean stones of a vivid primary green hue (as described above) with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone command the highest prices. This relative crystal non-uniformity makes emeralds more likely than other gemstones to be cut into cabochons, rather than faceted shapes.Sony VAIO VGN-CS50B/W Battery

Treatments

Most emeralds are oiled as part of the post lapidary process, in order to improve their clarity. Cedar oil, having a similar refractive index, is often used in this generally accepted practice. Other liquids, including synthetic oils and polymers with refractive indexes close to that of emerald such as Opticon are also used. Sony VAIO VGN-CS51B/W Battery

TheU.S. Federal Trade Commission requires the disclosure of this treatment when a treated emerald is sold. The use of oil is traditional and largely accepted by the gem trade. Other treatments, for example the use of green-tinted oil, are not acceptable in the trade. The laboratory community has recently standardized the language for grading the clarity of emeralds. Sony VAIO VGN-CS52JB/W Battery

Gems are graded on a four step scale; none, minor, moderate and highly enhanced. Note that these categories reflect levels of enhancement not clarity. A gem graded none on the enhancement scale may still exhibit visible inclusions. Laboratories tend to apply these criteria differently. Sony VAIO VGN-CS60B/P Battery

Some gem labs consider the mere presence of oil or polymers to constitute enhancement. Others may ignore traces of oil if the presence of the material does not materially improve the look of the gemstone.

Given that the vast majority of all emeralds are treated as described above, and the fact that two stones that appear to be similar in quality may actually be quite far apart in treatment level, Sony VAIO VGN-CS60B/Q Battery

a consumer considering a purchase of an expensive emerald is well advised to insist upon a treatment report from a reputable gemological laboratory. All other factors being equal, a high quality emerald with an enhancement level graded moderate should cost 40–50% less than an identical stone graded none.Sony VAIO VGN-CS60B/R Battery

Emerald localities

Emeralds in antiquity[when?] were mined by the Egyptians and in India and Austria.

A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia. A trapiche emerald exhibits a "star" pattern; it has raylike spokes of dark carbon impurities that give the emerald a six-pointed radial pattern.Sony VAIO VGN-CS61B/P Battery

Emeralds come from three main emerald mining areas in Colombia: Muzo, Coscuez, and Chivor. Emeralds are also found in other countries, such asAfghanistan, Australia, Austria, Brazil, Bulgaria, Cambodia, Canada, China, Egypt, Ethiopia, France, Germany, India, Italy, Kazakhstan,Madagascar,

Mozambique,Sony VAIO VGN-CS61B/Q Battery

Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania, United States,Zambia and Zimbabwe.  In the US, emeralds have been found in Connecticut, Montana, Nevada, North Carolina and South Carolina.[1] In 1998 emeralds were discovered in the Yukon. Sony VAIO VGN-CS61B/R Battery

Synthetic emerald

Emerald is a rare and valuable gemstone and, as such, it has provided the incentive for developing synthetic emeralds. Both hydrothermal and flux-growth synthetics have been produced, and a method has been developed for producing an emerald overgrowth on colorless beryl. Sony VAIO VGN-CS62JB/P Battery

The first commercially successful emerald synthesis process was that of Carroll Chatham. Because Chatham's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium, a lithium vanadate flux process is probably involved. The other large producer of flux emeralds was Pierre Gilson Sr., which has been on the market since 1964.Sony VAIO VGN-CS62JB/Q Battery

Gilson's emeralds are usually grown on natural colorless beryl seeds which become coated on both sides. Growth occurs at the rate of 1 mm per month, a typical seven-month growth run producing emerald crystals of 7 mm of thickness. Gilson sold his production laboratory to a Japanese firm in the 1980s, but production has ceased since; so did Chatham's, after the San Francisco earthquake in 1989.Sony VAIO VGN-CS62JB/R Battery

Hydrothermal synthetic emeralds have been attributed to IG Farben, Nacken, Tairus, and others, but the first satisfactory commercial product was that of Johann Lechleitner of Innsbruck, Austria, which appeared on the market in the 1960s. Sony VAIO VGN-CS71B/W Battery

These stones were initially sold under the names "Emerita" and "Symeralds", and they were grown as a thin layer of emerald on top of natural colorless beryl stones. Although not much is known about the original process, it is assumed that Leichleitner emeralds were grown in acid conditions.Sony VAIO VGN-CS72JB/W Battery

Later, from 1965 to 1970, theLinde Division of Union Carbide produced completely synthetic emeralds by hydrothermal synthesis. According to their patents, acidic conditions are

essential to prevent the chromium (which is used as the colorant) from precipitating.Sony VAIO VGN-CS90HS Battery

Also, it is important that the silicon-containing nutrient be kept away from the other ingredients to prevent nucleation and confine growth to the seed crystals. Growth occurs by a diffusion-reaction process, assisted by convection. The largest producer of hydrothermal emeralds today is Tairus in Russia. Sony VAIO VGN-CS90NS Battery

They have succeeded to synthesize emeralds that have similar chemical composition as emeralds in alkaline deposits in Colombia, hence they are called “Colombian Created Emeralds” or “Tairus Created Emeralds”. Luminescence in ultraviolet light is considered a supplementary test when making a natural vs. synthetic determination, as many, but not all, natural emeralds are inert to ultraviolet light. Many synthetics are also UV inert. Sony VAIO VGN-CS90S Battery

Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is the same as their natural counterparts. The U.S. Federal Trade Commission (FTC) has very strict regulations as to what can and what cannot be called "synthetic" stone. Sony VAIO VGN-CS91HS Battery

The FTC says: "§ 23.23(c) It is unfair or deceptive to use the word "laboratory-grown," "laboratory-created," "[manufacturer name]-created," or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named."Sony VAIO VGN-CS91NS Battery

Emerald in different cultures, and emerald lore

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs ofTaurus, Cancer and sometimes Gemini. Sony VAIO VGN-CS91S Battery

One of the quainter anecdotes on emeralds was by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America. On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor Sony VAIO VGN-CS92DS Battery

("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearl (to which he dedicated a work, Sony VAIO VGN-CS92JS Battery

A beautiful and incomparable pearl), and even for the death of King Charles IX of France, who died soon after."The Attenbury Emeralds" is a detective story in which Lord Peter Wimsey must solve several emerald-related mysteries. In The Wizard of Oz, the Wizard lives in a city made entirely of emerald, known as the Emerald City.Sony VAIO VGN-CS92XS Battery

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs ofTaurus, Cancer and sometimes Gemini. One of the quainter anecdotes on emeralds was by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America.Sony VAIO VGN-FW11E Battery

On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor ("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearl (to which he dedicated a work, A beautiful and incomparable pearl),Sony VAIO VGN-FW11L Battery

and even for the death of King Charles IX of France, who died soon after. "The Attenbury Emeralds" is a detective story in which Lord Peter Wimsey must solve several emerald-related mysteries. In The Wizard of Oz, the Wizard lives in a city made entirely of emerald, known as the Emerald City.Sony VAIO VGN-FW11M Battery

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs ofTaurus, Cancer and sometimes Gemini. One of the quainter anecdotes on emeralds was by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America.Sony VAIO VGN-FW11S Battery

On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor ("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pear Sony VAIO VGN-FW11ZU Battery

l (to which he dedicated a work, A beautiful and incomparable pearl), and even for the death of King Charles IX of France, who died soon after.  "The Attenbury Emeralds" is a detective story in which Lord Peter Wimsey must solve several emerald-related mysteries. In The Wizard of Oz, the Wizard lives in a city made entirely of emerald, known as the Emerald City.Sony VAIO VGN-FW139E/H Battery

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs ofTaurus, Cancer and sometimes Gemini. One of the quainter anecdotes on emeralds was by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America. Sony VAIO VGN-FW140AE Battery

On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor ("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearlSony VAIO VGN-FW140D Battery

(to which he dedicated a work, A beautiful and incomparable pearl), and even for the death of King Charles IX of France, who died soon after. "The Attenbury Emeralds" is a detective story in which Lord Peter Wimsey must solve several emerald-related mysteries. In The Wizard of Oz, the Wizard lives in a city made entirely of emerald, known as the Emerald City.Sony VAIO VGN-FW140E Battery

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs ofTaurus, Cancer and sometimes Gemini. One of the quainter anecdotes on emeralds was by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America.Sony VAIO VGN-FW140E/H Battery

On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor ("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearl  Sony VAIO VGN-FW140E/W Battery

(to which he dedicated a work, A beautiful and incomparable pearl), and even for the death of King Charles IX of France, who died soon after. "The Attenbury Emeralds" is a detective story in which Lord Peter Wimsey must solve several emerald-related mysteries. In The Wizard of Oz, the Wizard lives in a city made entirely of emerald, known as the Emerald City.Sony VAIO VGN-FW140FE Battery

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs ofTaurus, Cancer and sometimes Gemini. One of the quainter anecdotes on emeralds was by the 16th-century historian Brantôme, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America.Sony VAIO VGN-FW140N Battery

On one of Cortez's most notable emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor ("Among those born of woman there hath not arisen a greater," Matthew 11:11) which referred to John the Baptist. Sony VAIO VGN-FW140N/W Battery

Brantôme considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez's loss of an extremely precious pearl (to which he dedicated a work, A beautiful and incomparable pearl), and even for the death of King Charles IX of France, who died soon after.Sony VAIO VGN-FW145E Battery

"The Attenbury Emeralds" is a detective story in which Lord Peter Wimsey must solve several emerald-related mysteries. In The Wizard of Oz, the Wizard lives in a city made entirely of emerald, known as the Emerald City.Sony VAIO VGN-FW145E/W Battery,Sony VAIO VGN-FW160AE Battery,Sony VAIO VGN-FW160D Battery,Sony VAIO VGN-FW160E Battery,Sony VAIO VGN-FW160E/H Battery

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