Emerald crystal

Espig A process for making synthetic emeralds by the flux reaction technique. Beryllia and alumina are dissolved in molten lithium molybdate, and silica is floated on the melt. The emerald crystals form at the base of the melt, but because they tend to float and mix with the silica, a platinum screen is suspended in the middle of the melt. Invented by H. Espig. 

Figure 6.2. Cathodoluminescence tomograph of an emerald crystal synthesized by the high-temperature solution growth method. Note the regularly spaced faint growth banding appearing in between two distinct bands. (By courtesy of T. Miyata.)...

In the Muzo and Chivor mines, in Colombia, calcite veins, in which emerald crystals occur, develop, and they fill the cracks of sedimentary slate rock. Compared with emeralds occurring in basic metamorphic rocks, like those in the Urals, South Africa, or India, Colombian emerald crystals have a higher perfection, fewer inclusions, and attract higher evaluations as gemstones, since crystals grew freely in a hydrothermal solution. 

Emerald (Cr3+ Be3Al2(Si03)6, chromium-doped beryllium aluminium silicate or beryl) is a well known gem, and its beautiful green color has been attracted people for a long time. Nowadays, emerald crystal is also known as a tunable solid-state laser material, and its optical properties have been smdied (1-10). 

A An emerald crystal, which is based on the mineral beryl, embedded in a calcite matrix. 

Synthetic gemstone materials often have multiple uses. Synthetic mby and colodess sapphire are used for watch bearings, unscratchable watch crystals, and bar-code reader windows. Synthetic quartz oscillators are used for precision time-keeping, citizen s band radio (CB) crystals, and filters. Synthetic mby, emerald, and garnets are used for masers and lasers (qv). 

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). 

Ms " clusters have 12 framework bonding electrons as has [BsHs]- (p. 161) the anions are also isoelectronic with the well-known cation [Bis]. Similarly, the alloy NaSn. 2.23 reacts with cryptand in ethylenediamine to give dark-red crystals of [Na(ciypt)]4 [Sng] the anion is the first example of a C41, unicapped Archi-median antiprism (Fig. 10. lOc) and differs from the >3/, structure of the isoelectronic cation [Bis] + which, in the salt Bi+[Bi9] +[HfCl6]5 (p. 591), features a tricapped trigonal prism, as in [BgHg] " (p. 153). The emerald green species [Pb9] , which is stable in liquid NH3 solution, has not so far proved amenable to isolation via ciyptand-complexed cations. 

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. 

A variety of minerals are prized for their exquisite beauty, rarity, and exceptional durability. These extraordinary materials are classified as gemstones. One such mineral, silica, with a chemical composition of SK>2 (silicon dioxide), exhibits several crystal structures. Several gemstones are crystalline forms of silica, including amethyst, aquamarine, emerald, garnet, peridot, topaz, tourmaline, and zircon J l... 

At last, you glimpse shining water through the trees ahead, and come to the shores of a great lake, set like a shining crystal in the emerald heart of the forest. In the center of the lake is a small island. You are wondering how to cross to it when a gentle voice speaks ... 

Figure 11.12. Temperature dependences of Cr1+ fluorescence lifetime in various host materials. Materials with low strength of crystal field (1) LiSAF (2) LiBAF<44> (3) LiCAF.(44) Materials with high strength of crystal field (4) alexandrite 1 4S (5) ruby (data from 20 to 300K obtained from Nelson and Sturge,(46) (hose from 300K and beyond by the author) (6) emerald.(42)...

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

Dilute mineral acids attack nickel to a varying extent. The metal dissolves readily in dilute nitric acid. Evaporation of the solution forms emerald green crystals of nickel nitrate hexahydrate, Ni(N03)2 61120. 

Emerald-green crystals orthorhombic structure density 1.455 g/cm at 17°C melts at 230°C soluble in water, alcohol, chloroform, benzene and toluene insoluble in ether. 

Zaratite Emerald greed cubic crystals density 2.6 g/cm insoluble in water soluble in ammonia and dilute acids. 

The hexahydrate forms emerald green monochnic crystals hygroscopic density 2.05 g/cm isomorphous with corresponding cobalt salt melts at 56.7°C loses water on heating, decomposing to nickel oxide very soluble in water aqueous solution acidic soluble in ethanol. 

Brinzolamide has been assayed by titration in glacial acetic acid using crystal violet T.S. (USP) as an indicator. A 500-mg sample is dissolved in 50 mL of glacial acetic acid and titrated with 0. IN perchloric acid to an emerald green endpoint. 

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