chrysoberyl

He would often spend a whole day settling and resettling in their cases the various stones that be had collected, such as the olive-green chrysoberyl that turns red by lamplight, the cymophane with its wirelike line of silver, the pistachio-coloured peridot, rose-pink and wine-yellow topazes, carbuncles of fiery scarlet with tremulous, four-rayed stars, flame-red cinnamon-stones, orange and violet spinels, and amethysts with their alternate layers of ruby and sapphire.

Category one includes gemstones such as diamonds, sapphire, emerald, black opal, demantuit, alexandrite, chrysoberyl and all artificial gemstones made in modern ways.

In fact, amethysts, beryls, cat's-eye chrysoberyl, garnets, pearls, moonstones, sapphires and topazes were also mined from the southern part of India and the island of Sri Lanka, which also produced rubies.

The gem deposits (beryl, chrysoberyl, amethyst, corundum, etc.) of the Ratnapura (Sri Lanka) developed by transportation from gem-bearing source rocks and deposition in old stream terraces and flood plains such as well-rounded gravel or lenses of sand (Dissanayake et al., 2000).

The chemical elements beryllium (a major constituent in chrysoberyl) and chromium (the colouring agent in alexandrite) have contrasting chemical characteristics and do not as a rule occur together, usually being found in contrasting rock types.

The 'head' of the spicules in synthetic emeralds is usually composed of grains of synthetic phenakite, beryl, chrysoberyl, gold or other mineralizers (Choudhary and Golecha, 2007).

Exotic gems; v.2: how to identify and buy alexandrite, andalusite, chrysoberyl cat's-eye, kyanite, common opal, fire opal, dinosaur gembone, tsavorite, rhodolite & other garnets.

Especially since World War II, the pegmatites of the state of Minas Gerais have yielded some of the world's finest specimens of topaz, chrysoberyl, euclase, elbaite, and beryl (in all of its colored varieties); phosphate-rich pegmatites of the same state have furnished the world's finest specimens of brazilianite, beryllonite, eosphorite, hydroxylherderite, amblygonite and more; complex pegmatites of other kinds have provided cassiterite, xenotime, monazite and several rare-earth species; Brazilian specimens of titanite, phenakite, fluorapatite, kyanite, scheelite, spessartine and bertrandite are among the world's very best.

An outstanding example in the al-Sabah collection is a unique object--possibly a ceremonial case for a conch shell--in which gems, including chrysoberyl cat's eyes, are richly set in gold to create the figure of a mythic beast in a design typical of southern India.

Only three places in the world produce alexandrite, a gem derived from the mineral chrysoberyl: the USSR, Sri Lanka, and Brazil.

A gem variety of the mineral chrysoberyl that changes color from green in daylight to red in incandescent light, Alexandrite was named after Tsar Alexander II on the occasion of his coming of age, as its green and red colors were the same as the old Russian imperial colors.