Synthetic gems

L. H. Yaverbaum, Synthetic Gems, Noyes Data Corp., Park Ridge, N.J., 1980. 

Thallium oxide is used in manufacturing high coefficient of refraction optical glass (thallium flint glass). Also, the oxide is used to make synthetic gems. 

Traditionally, synthetic diamonds are made from graphite. Since the 1950s, scientists have known how to use pressure and heat to manufacture synthetic diamonds. Gradually, the quality of the synthetic gems has improved. Today, it is difficult to tell a good synthetic diamond from a natural stone. According to the American Museum of Natural History, currently about 80 tons of synthetic diamonds are manufactured each year. 

Although an interesting field, the cost of the technique, coupled with the decreased perceived value of synthetic gems as compared to real ones, rarely makes hydrothermal synthesis of gems economically feasible [69]. 

Why are flux growth methods widely used in the production of synthetic gems Are there are disadvantages that you can think of in using these methods for this particular application ... 

There is a large demand nowadays for single, pure and defect-free crystals of innumerable substances, e.g. for the scientific appraisal of the chemical and physical properties of pure solids, for use in solid-state electronics, where crystals of certain substances are required for their dielectric, piezoelectric, paramagnetic and semiconductor properties, and for optical and laser materials and synthetic gem-stones (see Table 7.1). 

Lindblom J, Hosla J, Papunen H et al (2003) Differentiation of natural and synthetic gem-quality diamonds by luminescence properties. Opt Mater 24 243-253 Lindblom J, Holsa J, Papunen H (2005) Luminescence study of defects in synthetic as-grown and HPHT diamonds compared to natural diamonds. Am Miner 90 428-440 Mayer I, Layani J, Givan A et al (1999) La ions in precipitated hydroapatites. J Inorg Biochem 73 221-226... 

Verneuil s method, although somewhat modified, is still widely used today for the manufacture of colored gemstones. When magnesium oxide is substituted for aluminum oxide, a colorless spinel-like product is formed. The addition of various transition metals then adds a tint to the spinel that results in the formation of synthetic emerald, aquamarine, tourmaline, or other gemstones. Synthetic gems look very much like their natural counterparts. 

Solid Solid Solid sol Ruby glass, certain natural and synthetic gems, blue rock salt, black diamond... 

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