Beryl (redirected from beryls)

beryl (bĕr`ĭl), mineral, a silicate of beryllium and aluminum, Be₃Al₂Si₆O₁₈, extremely hard, occurring in hexagonal crystals that may be of enormous size and are usually white, yellow, green, blue, or colorless. Beryl is commonly used as a gemstone. The refractive index is low, and the stones have little or no fire. The most valued variety of beryl is emerald. An aquamarine is a blue to sea-green beryl; morganites are rose-red beryls. It is the principal raw material for the element beryllium and its compounds.

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beryl

Mineral composed of beryllium aluminum silicate, Be₃Al₂(SiO₃)₆, a commercial source of beryllium. Several varieties are valued as gemstones: aquamarine (pale blue-green); emerald (deep green); heliodor (golden yellow); and morganite (pink). Before 1925 beryl was used only as a gemstone, but since then many important uses have been found for beryllium (e.g., in nuclear reactors, space vehicles, and X-ray tubes). No large deposits have been found, and most production is a by-product of the mining of feldspar and mica. Brazil is a major producer; others include Zimbabwe, South Africa, Namibia, and the U.S.

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beryl

a white, blue, yellow, green, or pink mineral, found in coarse granites and igneous rocks. It is a source of beryllium and used as a gemstone; the green variety is emerald, the blue is aquamarine. Composition: beryllium aluminium silicate. Formula: Be₃Al₂Si₆O₁₈. Crystal structure: hexagonal

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Beryl 

a mineral of the silicate class. Its chemical formula is Al₂Be₃(Si₆O₁₈), but because of the constant presence of alkalies (Na, Cs, Rb), Li, Mn, Fe²⁺, Fe³⁺, and Cr³⁺, and also water and gases (helium and argon), the composition of beryl is much more complicated. Various types of beryl—alkali-free, sodium, sodium-lithium, and lithium-cesium—are distinguished according to the alkali and lithium content. Beryl crystallizes in a hexagonal system, forming prismatic, acicular, or tabular crystals or complete granular masses. Beryl’s hardness on the mineralogical scale is 7.5, and its density is 2,650–2,800 kg/m³. The color of beryl is extremely varied. Depending upon the color, transparency, and impurities, the following types of beryl are distinguished: beryl proper—a green or yellowish-white cloudy crystal; aquamarine—transparent greenish-blue (the color of seawater) or dark blue crystals, colored with Fe²⁺ impurities; heliodor—yellow because of Fe²⁺ impurities; emerald—a transparent crystal of a deep grass-green color, colored by Cr³⁺; rosterite—colorless or pink owing to 5 percent or more Li¹⁺ and Cs¹⁺ impurities; and morganite—pink owing to Mn³⁺ impurities. Beryl forms in granitic pegmatites, greisens, skarns, and pneumatolytic-hydrothermal deposits of the metasomatic type. Beryl is one of the major minerals in beryl ore, from which beryllium is smelted. Transparent beautifully colored or clear crystals are cut to make high-quality precious stones.

REFERENCE

Beus, A. A. Geokhimiia berilliia i geneticheskie tipy berillievykh mestorozhdenii. Moscow, 1960. G. P. Barsanov