The mineral beryl is a beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, red, and white.
Etymology
The name beryl is derived (via Latin: Beryllus, Old French: beryl, and Middle English: beril) from Greek βήρυλλος beryllos which referred to a precious blue-green color-of-sea-water stone[1] and originated from Prakrit veruliya (वॆरुलिय) and Pali veḷuriya (वेलुरिय); veḷiru (भेलिरु) or, viḷar (भिलर्), "to become pale"; ultimately from Sanskrit वैडूर्य vaidurya-, which is of Dravidian origin, maybe from the name of Belur. The term was later adopted for the mineral beryl more exclusively. The word Βήρυλλος was abbreviated as βρυλλ brill which produced the Italian word brillare meaning "shine", the French word brille meaning "shine" and the English word brilliance.
Deposits
Beryl of various colors is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural Mountains, and limestone in Colombia. Beryl is often associated with tin and tungsten ore bodies. Beryl is found in Europe in Norway, Austria, Germany, Sweden (especially morganite), and Ireland, as well as Brazil, Colombia, Madagascar, Russia, South Africa, the United States, and Zambia. U.S. beryl locations are in California, Colorado, Connecticut, Idaho, Maine, New Hampshire, North Carolina, South Dakota and Utah.
New England's pegmatites have produced some of the largest beryls found, including one massive crystal from the Bumpus Quarry in Albany, Maine with dimensions 5.5 m by 1.2 m (18 ft by 4 ft) with a mass of around 18 metric tons; it is New Hampshire's state mineral. As of 1999, the largest known crystal of any mineral in the world is a crystal of beryl from Madagascar, 18 meters long and 3.5 meters in diameter.
Varieties
Etymology
The name beryl is derived (via Latin: Beryllus, Old French: beryl, and Middle English: beril) from Greek βήρυλλος beryllos which referred to a precious blue-green color-of-sea-water stone[1] and originated from Prakrit veruliya (वॆरुलिय) and Pali veḷuriya (वेलुरिय); veḷiru (भेलिरु) or, viḷar (भिलर्), "to become pale"; ultimately from Sanskrit वैडूर्य vaidurya-, which is of Dravidian origin, maybe from the name of Belur. The term was later adopted for the mineral beryl more exclusively. The word Βήρυλλος was abbreviated as βρυλλ brill which produced the Italian word brillare meaning "shine", the French word brille meaning "shine" and the English word brilliance.
Deposits
Beryl of various colors is found most commonly in granitic pegmatites, but also occurs in mica schists in the Ural Mountains, and limestone in Colombia. Beryl is often associated with tin and tungsten ore bodies. Beryl is found in Europe in Norway, Austria, Germany, Sweden (especially morganite), and Ireland, as well as Brazil, Colombia, Madagascar, Russia, South Africa, the United States, and Zambia. U.S. beryl locations are in California, Colorado, Connecticut, Idaho, Maine, New Hampshire, North Carolina, South Dakota and Utah.
New England's pegmatites have produced some of the largest beryls found, including one massive crystal from the Bumpus Quarry in Albany, Maine with dimensions 5.5 m by 1.2 m (18 ft by 4 ft) with a mass of around 18 metric tons; it is New Hampshire's state mineral. As of 1999, the largest known crystal of any mineral in the world is a crystal of beryl from Madagascar, 18 meters long and 3.5 meters in diameter.
Varieties
Aquamarine and maxixe
Aquamarine (from Lat. aqua marina, "water of the sea") is a blue or turquoise variety of beryl. It occurs at most localities which yield ordinary beryl, some of the finest coming from Russia. The gem-gravel placer deposits of Sri Lanka contain aquamarine. Clear yellow beryl, such as occurs in Brazil, is sometimes called aquamarine chrysolite. When corundum presents the bluish tint of typical aquamarine, it is often termed Oriental aquamarine. The deep blue version of aquamarine is called maxixe. Its color fades to white when exposed to sunlight or is subjected to heat treatment, though the color returns with irradiation.
The pale blue color of aquamarine is attributed to Fe2+. The Fe3+ ions produce golden-yellow color, and when both Fe2+ and Fe3+ are present, the color is a darker blue as in maxixe. Decoloration of maxixe by light or heat thus may be due to the charge transfer Fe3+ and Fe2+. Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy particles (gamma rays, neutrons or even X-rays).
In the United States, aquamarines can be found at the summit of Mt. Antero in the Sawatch Range in central Colorado. In Wyoming, aquamarine has been discovered in the Big Horn Mountains, near Powder River Pass. In Brazil, there are mines in the states of Minas Gerais, Espírito Santo, and Bahia, and minorly in Rio Grande do Norte. The Mines of Colombia, Zambia, Madagascar, Malawi, Tanzania and Kenya also produce aquamarine.
The biggest aquamarine ever mined was found at the city of Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm (19 in) long and 42 cm (17 in) in diameter.
Emerald
Emerald refers to green beryl, colored by trace amounts of chromium and sometimes vanadium. The word "emerald" comes (via Middle English: Emeraude, imported from Old French: Ésmeraude and Medieval Latin: Esmaraldus) from Latin smaragdus from Greek smaragdos - σμάραγδος ("green gem"), its original source being a Semitic word izmargad (אזמרגד) or the Sanskrit word, marakata (मरकन), meaning "green". Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor.
Emeralds in antiquity were mined by the Egyptians and in Austria, as well as Swat in northern Pakistan. 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. It is named for the trapiche, a grinding wheel used to process sugarcane in the region. Colombian emeralds are generally the most prized due to their transparency and fire. Some of the most rare emeralds come from three main emerald mining areas in Colombia: Muzo, Coscuez, and Chivor. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. In the US, emeralds can be found in Hiddenite, North Carolina. In 1998, emeralds were discovered in the Yukon.
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. The first commercially successful emerald synthesis process was that of Carroll Chatham. The other large producer of flux emeralds was Pierre Gilson Sr., which has been on the market since 1964. 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. The green color of emeralds is attributed to presence of Fe3+ and Fe2+ ions.
Golden beryl and heliodor
Golden beryl can range in colors from pale yellow to a brilliant gold. Unlike emerald, golden beryl has very few flaws. The term "golden beryl" is sometimes synonymous with heliodor (from Greek hēlios - ἥλιος "sun" + dōron - δῶρον "gift") but golden beryl refers to pure yellow or golden yellow shades, while heliodor refers to the greenish-yellow shades. The golden yellow color is attributed to Fe3+ ions. Both golden beryl and heliodor are used as gems. Probably the largest cut golden beryl is the flawless 2054 carat stone on display in the Hall of Gems, Washington, D.C
Goshenite
Goshenite
Colorless beryl is called goshenite. The name originates from Goshen, Massachusetts where it was originally described. Since all these color varieties are caused by impurities and pure beryl is colorless, it might be tempting to assume that goshenite is the purest variety of beryl. However, there are several elements that can act as inhibitors to color in beryl and so this assumption may not always be true. The name goshenite has been said to be on its way to extinction and yet it is still commonly used in the gemstone markets. Goshenite is found to some extent in almost all beryl localities. In the past, goshenite was used for manufacturing eyeglasses and lenses owing to its transparency. Nowadays, it is most commonly used for gemstone purposes and also considered as a source of beryllium.
The gem value of goshenite is relatively low. However, goshenite can be colored yellow, green, pink, blue and in intermediate colors by irradiating it with high-energy particles. The resulting color depends on the content of Ca, Sc, Ti, V, Fe, and Co impurities.
Morganite
Morganite, also known as "pink beryl", "rose beryl", "pink emerald", and "cesian beryl", is a rare light pink to rose-colored gem-quality variety of beryl. Orange/yellow varieties of morganite can also be found, and color banding is common. It can be routinely heat treated to remove patches of yellow and is occasionally treated by irradiation to improve its color. The pink color of morganite is attributed to Mn2+ ions.
Pink beryl of fine color and good sizes was first discovered on an island on the coast of Madagascar in 1910. It was also known, with other gemstone minerals, such as tourmaline and kunzite, at Pala, California. In December 1910,the New York Academy of Sciences named the pink variety of beryl "morganite" after financier J. P. Morgan.
The Rose of Maine
On October 7, 1989, one of the largest gem morganite specimens ever uncovered, eventually called "The Rose of Maine," was found at the Bennett Quarry in Buckfield, Maine, USA. The crystal, originally somewhat orange in hue, was 23 cm (9 in) long and about 30 cm (12 in) across, and weighed (along with its matrix) just over 50 lbs (23 kg).
Red beryl
Red beryl (also known as "red emerald" or "scarlet emerald") is a red variety of beryl. It was first described in 1904 for an occurrence, its type locality, at Maynard's Claim (Pismire Knolls), Thomas Range, Juab County, Utah, USA. The old synonym bixbite is deprecated from the CIBJO, because of the risk of confusion with the mineral bixbyite (also named after the mineralogist Maynard Bixby). The dark red color of bixbite is attributed to Mn3+ ions.
Red beryl is very rare and has only been reported from a handful of locations including: Wah Wah Mountains, Beaver County, Utah; Paramount Canyon, Sierra County, New Mexico; Round Mountain, Sierra County, New Mexico;[1] and Juab County, Utah. The greatest concentration of gem-grade red beryl comes from the Violet Claim in the Wah Wah Mountains of mid-western Utah, discovered in 1958 by Lamar Hodges, of Fillmore, Utah, while he was prospecting for uranium. Prices for top quality natural red beryl can be as high as $10,000 per carat for faceted stones. Red beryl has been known to be confused with pezzottaite, also known as raspberry beryl or "raspberyl", a gemstone that has been found in Madagascar and now Afghanistan - although cut gems of the two varieties can be distinguished from their difference in refractive index.
While gem beryls are ordinarily found in pegmatites and certain metamorphic rocks, bixbite occurs in topaz-bearing rhyolites. It formed by crystallizing under low pressure and high temperature from a pneumatolitic phase along fractures or within near-surface miarolitic cavities of the rhyolite. Associated minerals include bixbyite, quartz, orthoclase, topaz, spessartine, pseudobrookite and hematite. The red color is thought to be from manganese substituting for aluminium in the beryl structure.
From Wikipedia, the free encyclopedia
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part 2
The magic of colours
Colour appeals to our feelings directly. It makes us happy and cheerful, livens us up or calms us down, and has a magical or liberating effect. And where is colour more lastingly and more beautifully captured than in a gemstone? In the fascinating world of precious stones, emeralds glow in the fieriest green imaginable. Aquamarines sparkle in a whole range of blues – from the light blue of the sky to the deep blue of the sea. And the charming pink of morganite puts a spell on women the whole world over. Yet how many people are aware of the fact that these gems, different as they are, belong to a single family? Aquamarine, emerald and morganite are all beryls – just like golden beryl, yellowish-green heliodor, colourless goshenite and the rare red beryl. Whether blue, green, yellow, colourless or pink, their chemical and physical properties essentially correspond; it is only in their colours that they differ from one another so much.
So where does this diversity come from? It is an exciting and very ancient story, which began millions of years ago when the appropriate pressure and temperature conditions formed precious crystals in the centre of the Earth. Beryls are beryllium-aluminium-silicates. As pure beryl, they are colourless, but they are able on account of their structure to store various foreign substances, and it is these which give rise to the various colours, turning a plain, colourless gemstone into a green, yellow, pink or blue treasure.
Iron colours beryl in the most beautiful sea-blue hues, turning it into aquamarine, one of our best known and most popular gems. This gem not only shines in all the colours of water - fine blue shades which can complement almost any skin or eye colour - ; a slight green shimmer is also one of its typical features. Aquamarine is the favourite stone of many a creative designer and distinguishes itself by a whole series of good qualities: even distribution of the colour, inclusions which hardly spoil the effect at all, good hardness and a wonderful shine.
The emerald is closely related to the aquamarine. This most valuable of all the beryls is given the most beautiful, intense and glowing green imaginable, namely emerald green, by chrome and/or vanadium. Small crystal inclusions, cracks or fissures are not merely tolerated in this precious gemstone; they are actually regarded as features of its identity. Connoisseurs refer to them affectionately as the jardin (garden) of the emerald.
Beryl behaves quite differently when there is manganese involved. This element gives it a special feminine pink, turning it into morganite, without doubt the next best known representative of the beryl group after the classics, emerald and aquamarine. Formerly, it was known rather plainly as 'pink beryl'. It has only been called morganite since the year 1911, having been so named in honour of the New York finance expert and gemstone collector John Pierpont Morgan. This gemstone loves generosity, since it is only from a certain size upwards that the beauty of its colour, mostly ranging from a tender pink to a pale violet, is shown to its full advantage.
Small traces of iron, and a natural aura which emanates from minerals containing uranium, are sufficient to give a colourless beryl a more or less intense yellow tone - the typical colour of the golden beryl. This gem has practically the same good qualities as its light blue cousin, the aquamarine. Indeed, as a rule it is found in the same kind of deposit. Golden beryl holds a fascination with its fine spectrum of yellow hues, from a weak lemon yellow to a warm golden colour. Unlike the emerald, however, it seldom has inclusions.
Iron and uranium together are also responsible for the fresh, stimulating greenish yellow of another beryl variety, the heliodor. The name goes with the colour very well, being derived from the Greek helios (sun) and doron (gift). So heliodor is a 'gift from the sun' to Man.
Now and again, beryl is found which lacks these colouring substances. In such cases it simply remains a 'mere' colourless beryl. In the trade, it is more often referred to as goshenite after the place where it was originally found, Goshen, in Massachusetts. Colourless beryl is rare, and has little significance as a gemstone. It does, however, have some historical importance, having been the forerunner of today's spectacles. Even in ancient times, beryl was used to make glasses.
Originally, the name 'beryl' came from India. It was derived from the Sanskrit word 'veruliyam', an old term for the gemstone chrysoberyl, from which the Greek word 'beryllos' later developed.
Beryls are popular gems, not only on account of their magnificent colours. Their appeal also lies in their high brilliance and qualities such as their hardness (7.5 to 8), which makes them admirably well suited for use in jewellery. The typical hexagonal beryl crystals with their often vertically striated surfaces are mainly found in the gemstone deposits of South America and those of Central and West Africa. However, they also occur on Madagascar, in Russia and the Ukraine, and in the USA. The skilled hands of gemstone cutters turn them into a multitude of many-faceted shapes. In particular, beryls are well suited to rectangular or square step cuts, since it takes a clear design to bring out the transparent beauty of this colourful gemstone family to the full.
