Emerald, beryl

Photos of four silicate minerals, red beryl, emerald, mica, and asbestos. Silicates take many forms, depending on the detailed structure of the Si—O bonding network. 

Beryllium (Be) or Glucinum, at wt 9.02, It grey metal, d 1.842, mp 1284° bp 2767°[Lange( 1956)] mp 1350° bp 1530°(ChemRubHdb) insol in cold w in nitric acid si sol in hot w with decompn sol in HCl, dil sulfuric acid in alks. It does not oxidize at ordinary temp but when heated in the powder form burns brilliantly in air. It does not react with steam even at a red heat. Can be prepd by the electrolysis of a fused mixt of Be chloride with Na or Amm chlorides, or of the fluoride with NaF in a nickel crucible with a carbon anode. Be was discovered ca 1797 in the form of the oxide by Vauquelin as a constituent of the mineral beryl (emerald) (Refs 1-5)... 

Uses of beryllium and beryllium oxide. Beryl, emerald. 

Beryl Emerald Intense green or bluish green... 

Figure 12.21 The beauty of crystalline solids. A, Wulfenite. B, Barite (left) on calcite (right). C, Beryl (emerald). D, Quartz (amethyst).

Gr. beryllos, beryl also called Glucinium or Glucinum, Gr. glykys, sweet) Discovered as the oxide by Vauquelin in beryl and in emeralds in 1798. The metal was isolated in 1828 by Wohler and by Bussy independently by the action of potassium on beryllium chloride. 

Beryllium is found in some 30 mineral species, the most important of which are bertrandite, beryl, chrysoberyl, and phenacite. Aquamarine and emerald are precious forms of beryl. Beryl and bertrandite are the most important commercial sources of the element and its compounds. Most of the metal is now prepared by reducing beryllium fluoride with magnesium metal. Beryllium metal did not become readily available to industry until 1957. 

Beryl. Beryl [1302-52-9] Be Al Si O g, is called aquamarine [1327-51 -1] when pale green or blue from inclusion of Fe emerald [12415-33-7] when dark green from Cr or at times V, and morganite or red beryl when pink or red, respectively, from Mn. Only the synthetic emerald is in commercial production, although the other colors can also be grown. Both the flux and hydrothermal techniques are used to grow this luxury synthetic. 

A thin layer of dark green beryl had been grown by a hydrothermal technique over the surface of a pale beryl to imitate emerald. It has been suggested that such stones should be called synthetic emerald-beryl doublets (16). The abiHty to grow thin, but not thick, single-crystal diamond on the surface of natural diamond (17) leads to the possibiHty of growing such a thin film colored blue with boron this has been done experimentally (18). 

The discovery of beryllium in 1798 followed an unusual train of events. The mineralogist R.-J. Haiiy had observed the remarkable similarity in external crystalline structure, hardness and density of a beryl from Limoges and an emerald from Peru, and suggested to L.-N. Vauquelin that he should analyse them to see if they were chemically identical. As a result, Vauquelin showed... 

Both beryl and emerald were found to be essentially Be3Al2Si O g, the only difference between them being that emerald also contains 2% Cr, the source of its green colour. The combining weight of Be was 4.7 but the similarity (diagonal relation) between Be and... 

A siinilar observation had been made (with less dramatic consequences) nearly 2000 y earlier by Pliny the Elder when he wrote Beryls, it is thought, are of the same nature as the smaragdus (emerald), or at leasi closely analogous (Historia Nuturalis, Book 37). 

FIGURE 14.20 An emerald is a crystal of beryl with some Cr + ions, which are responsible for the green color. 

A colorless mineral known as corundum (composed of aluminum oxide) is colorless. A red variety of corundum known as ruby, a precious stone, owes its color to impurities of chromium within the crystal structure of corundum. Blue and violet varieties of corundum are classified as sapphires, the blue being the result of iron and titanium impurities, and the violet of vanadium impurities within the corundum crystal structure. Another colorless mineral is beryl (composed of beryllium aluminum silicate) but blue aquamarine, green emerald, and pink morganite, are precious varieties of beryl including different impurities aquamarine includes iron, emerald chromium and vanadium, and morganite manganese. 

Emerald Gemstone A variety of beryl Very hard... 

Mineral gemstones that have the same basic chemical composition, that is, are composed of the same major elements and differ only in color, are considered as variations of the same mineral species. As gemstones, however, minerals that have the same composition and crystalline structure but exhibit different colors are classified as different gemstones. Beryl, for example, a mineral (composed of beryllium aluminum silicate), includes a pink variety, known by the gemstone name of morganite, and also a well-known green variety, emerald. Table 18 lists and classifies, by composition and color, gemstones that have been appreciated since antiquity. 

From the days of the Egyptians, when emeralds were a particular favorite of kings, beryl has also been a favored gemstone. It was not until the late eighteenth century that Abbe Rene Just Haiiy (1743—1822), the father of crystallography, studied the crystalline structures and densities of emeralds and beryl and determined that they were the same mineral. At about the same time, in 1798, Louis-Nicolas Vauquehn (1763—1829) discovered that both emeralds and beryl were composed of a new element with four protons in its nucleus. The element was named glucina because of its sweet taste. It was not until the nineteenth century that the metal berylhum was extracted from berylhum chloride (BeCy by chemical reactions. Late in the nineteenth century, E Lebeau (dates unknown) separated the metal by the electrolytic process. 

French chemist Louis-Nicolas Vauquelin Rare alkaline-earth metal derived from the mineral beryl of which emeralds and aquamarines are crystals. 

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