Home Gemstone Beryl

Beryl

SHARE

Beryl is a member of cyclosilicate minerals with composed of  beryllium aluminium. Chemical formula: Be3Al2Si6O18. Few people have ever heard of the mineral beryl but almost everyone has heard of its principal gemstone varieties emerald and aquamarine. Before 1925, beryl’s solitary use was as a gemstone but since then many important uses have been found for beryllium. As a result, common beryl, which is usually pale green or white, has become widely sought after as the ore of this rare element. Most beryl is found in granite ,pegmatites, and rhyolites, but it can also occur in metamorphic rocks, such as schists. Emerald owes its grass-green color to the presence of traces of chromium and sometimes vanadium. Flawless emeralds are rare, but since 1937 the manufacture of synthetic crystals has become possible. Aquamarine is the most common gemstone variety of beryl. Nearly always found in cavities in pegmatites or in alluvial deposits, it forms larger and clearer crystals than emerald. Other gemstone varieties of beryl include heliodor, morganite, and goshenite. (Bonewitz, 2012)

Name: The name beryl is of ancient origin, derived from the Greek word which was applied to green gem stones.

Association: Quartz, feldspar, muscovite, lepidolite, spodumene, amblygonite, tourmaline, topaz, cassiterite, columbite, tantalite.

Crystallography: Hexagonal; dihexagonal-dipyramidal. Strong prismatic habit. Frequently vertically striated and grooved. Forms usually present consist only of prism of first order {10T0} and base {0001}. Dihexagonal forms are rare. Crystals frequently of considerable size with rough faces. Also found massive, with indistinct columnar aggregates or granular.

Beryl Composition: Beryllium aluminum silicate, Be3Al2Si60i8. BeO = 14.0 per cent, A120 3 = 19.0 per cent, Si02 = 67.0 per cent. Small amounts of the alkali oxides, often in part consisting of cesium oxide, frequently replace the beryllium oxide

Diagnostic Features: Recognized usually by its hexagonal crystal , form and color. Distinguished from apatite by greater hardness.

Similar Species: Euclase, Be2Al2(Si04)2(OH)2, and gadoliniie, Ye,Fe” Be2(Si04)202, are rare beryllium silicates.

Varieties of Beryl

Aquamarine and maxixe

Aquamarine is a blue or cyan form of beryl. It happens at maximum localities which yield regular beryl. The gem-gravel placer deposits of Sri Lanka comprise aquamarine. green-yellow beryl, which includes that going on in Brazil, is every now and then known as chrysolite aquamarine. The deep blue version of aquamarine is known as maxixe. Maxixe is usually discovered in the United States of America of Madagascar. Its color fades to white while exposed to daylight or is subjected to heat treatment, though the colour returns with irradiation.

Emerald

Emerald is green beryl, colored by means of trace quantities of chromium and on occasion vanadium. maximum emeralds are enormously blanketed, so their brittleness (resistance to breakage) is assessed as usually poor.

 Emeralds in antiquity had been mined through the Egyptians and in what is now Austria, in addition to Swat in modern Pakistan. an extraordinary sort of emerald called a trapiche emerald is from time to time determined in the mines of Colombia. A trapiche emerald exhibits a “megastar” pattern; it has raylike spokes of dark carbon impurities that provide the emerald a six-pointed radial pattern. It is named for the trapiche, a grinding wheel used to system sugarcane inside the area. Colombian emeralds are typically the maximum prized due to their transparency and hearth. a number of the rarest emeralds come from the 2 important emerald belts within the jap levels of the Colombian Andes: Muzo and Coscuez west of the Altiplano Cundiboyacense, and Chivor and Somondoco to the east. best emeralds are also determined in different international locations, including Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia. in the US, emeralds may be found in Hiddenite, North Carolina. In 1998, emeralds were determined in Yukon.

Golden beryl and heliodor

Golden beryl can range in shades from pale yellow to a terrific gold, not like emerald, golden beryl commonly has only a few flaws. The term “golden beryl” is once in a while synonymous with heliodor (from Greek hēlios – ἥλιος “solar” + dōron – δῶρον “present”) but golden beryl refers to natural yellow or golden yellow sunglasses, whilst heliodor refers back to the greenish-yellow sunglasses. The golden yellow color is attributed to Fe3+ ions. each golden beryl and heliodor are used as gemstones. in all likelihood the largest reduce golden beryl is the perfect 2054-carat stone on display inside the corridor of gemstones, Washington, D.C., U.S..

Goshenite

Colorless beryl is known as goshenite. The name originates from Goshen, Massachusetts, where it turned into at the start determined. In the past, goshenite was used for manufacturing eyeglasses and lenses owing to its transparency. these days, it’s miles maximum commonly used for gemstone purposes.

The gem price of goshenite is enormously low. but, goshenite may be colored yellow, inexperienced, pink, blue and in intermediate colorations by way of irradiating it with high-energy particles. The resulting shade depends at the content material of Ca, Sc, Ti, V, Fe, and Co impurities.

Morganite

Morganite, additionally referred to as “red beryl”, “rose beryl” “crimson emerald” (which isn’t always a criminal term to be used as per the brand new Federal exchange commission recommendations and rules), and “cesian (or caesian) beryl”, is a unprecedented mild crimson to rose-coloured gem-best sort of beryl. Orange/yellow types of morganite also can be observed, and coloration banding is commonplace. it may be routinely heat handled to cast off patches of yellow and is every now and then handled by irradiation to enhance its shade. The purple shade of morganite is attributed to Mn2+ ions.

Red beryl

Red beryl (previously known as “bixbite” and advertised as “crimson emerald” or “scarlet emerald” but be aware that both latter terms concerning “Emerald” terminology at the moment are prohibited in the america under Federal exchange fee guidelines) is a pink type of beryl. It was first described in 1904 for an occurrence, its type locality, at Maynard’s declare (Pismire Knolls), Thomas range, Juab County, Utah. The vintage synonym “bixbite” is deprecated from the CIBJO, because of the threat of bewilderment with the mineral bixbyite (each have been named after the mineralogist Maynard Bixby). The dark purple color is attributed to Mn3+ ions.

Chemical Properties

Chemical Classification Silicates Mineral, Cyclosilicate
Formula Be3Al2Si6O18
Common Impurities Fe,Mn,Mg,Ca,Cr,Na,Li,Cs,O,H,OH,H2O,K,Rb

Beryl Physical Properties

Crystal habit Prismatic to tabular crystals; radial, columnar; granular to compact massive
Color Colorless, green, blue, yellow, white, pink, etc.
Streak White
Luster Vitreous, Sub-Vitreous, Waxy, Greasy
Cleavage Imperfect/Fair {0001}
Diaphaneity Transparent to translucent
Mohs Hardness 7.5–8
Crystal System Hexagonal
Tenacity Brittle
Density 2.63 – 2.92 g/cm3 (Measured)   
Fracture Conchoidal

Beryl Optical Properties

Color / Pleochroism Weak to distinct
RI values: nω = 1.568 – 1.602 nε = 1.564 – 1.595
Twinning Rare
Optic Sign Uniaxial (-)
Birefringence δ = 0.004 – 0.007
Relief Moderate

Occurrence of Beryl

Beryl, although containing the rare element beryllium, is rather common and widely distributed. It occurs usually in granitic rocks, either in druses or in pegmatite dikes. It is also found in mica schists and associated with tin ores. Emeralds of gem quality occur in a dark bituminous limestone at Muso, 65 miles northwest of Bogota, Colombia. This locality has been worked almost continually since the middle of the sixteenth century, and has furnished the greater part of the emeralds of the world. Another famous locality for emeralds is in Siberia on the river Takowaja, 45 miles east of Sverdlovsk. There they occur in a mica schist associated with phenacite, chrysoberyl, rutile. Rather pale emeralds have been found in small amount in Alexander County, North Carolina, associated with the green variety of spodumene, hiddenite. Beryl of the lighter aquamarine color is much more common, and is found in gem quality in Brazil and Siberia. Also in Madagascar. In the United States gem beryls, chiefly aquamarine, have been found in various places in Maine, New Hampshire, Massachusetts, Connecticut, North Carolina, Colorado. Golden beryl has been found in Maine, Connecticut, North Carolina, and Pennsylvania; also in Siberia and Ceylon. Rose-colored beryl has been found in San Diego County, California, associated with pink tourmaline and the pink spodumene, kunzite. A similar occurrence in Madagascar has furnished magnificent rose-colored stones.

Uses Area

Used as a gem stone of various colors. The emerald ranks as the most valuable of stones, and may have a much greater value than the diamond. Beryl is also used as a source of beryllium.

Beryl Distribution Area

Prominent localities fine specimens include:

  • Russia, in the MursinkaAlabashka area, near Yekaterinburg (Sverdlovsk), Ural Mountains, and from Nerchinsk south to Borzya, Adun-Chilon Mountains, Siberia.
  • At Volhynia, Ukraine.
  • In the Muiane pegmatite, Alto Ligonha district, Mozambique.
  • From Madagascar, especially around Mt. Bity, south of Antsirabe, with giant crystals from the Malakialina district.
  • In the Ran-Gabas Hills, near Jos, Nigeria.
  • In the Sandawana-Belingwe area, Mweza Range, Zimbabwe.
  • Exceptional green crystals from the Muzo and Chivor districts, Boyaca Province, Colombia.
  • In Brazil, from Minas Gerais, in large districts around Teolo Otoni, Governador Valadares, Conselheiro Pena, and Itabira.
  • Around Mingora, Swat district; from Dassu and the Skardu district; at Kunar and Nagar, near Karimabad, Hunza district, Pakistan.
  • In Afghanistan, around Khenj, Panjshir Valley.
  • In the USA, from the Pala and Rincon districts, San Diego Co., California; at Hiddenite, Alexander Co., North Carolina; fine red crystals in the Wah Wah Mountains, Beaver Co., Utah; on Mt. Antero,öColorado; and in the Sawtooth Mountains area, Idaho.

References

• Bonewitz, R. (2012). Rocks and minerals. 2nd ed. London: DK Publishing.
• Dana, J. D. (1864). Manual of Mineralogy… Wiley.
• Handbookofmineralogy.org. (2019). Handbook of Mineralogy. [online] Available at: http://www.handbookofmineralogy.org [Accessed 4 Mar. 2019].
• Mindat.org. (2019): Mineral information, data and localities.. [online] Available at: https://www.mindat.org/ [Accessed. 2019].
• Wikipedia contributors. (2019, July 1). Beryl. In Wikipedia, The Free Encyclopedia. Retrieved 01:29, July 5, 2019, from https://en.wikipedia.org/w/index.php?title=Beryl&oldid=904367769

Cite this article as: Geology Science. (2019). Beryl. [online] Available at: http://geologyscience.com/minerals/beryl/ [21st October 2019 ]
SHARE