The color of topaz should be the primary color, mainly trivalent iron for coloring. In terms of yield, it is a rare variety in Hetian jade. Generally, aniseed is rare, mostly green, yellow-green, and orthochromatic yellow material is rare. This material has fine texture and good oiliness, but the raw materials are easy to crack and the processing yield is low.

If the primary mineral seed crystal topaz is dyed, its color will become slightly dark brownish yellow or brownish red, which is very delicate and uniform, with red or black spots in some areas. The primary mineral topaz and seed topaz are the two most authentic topaz in Hotan, Xinjiang, especially the primary mineral topaz.

Extended data:

The chemical composition of topaz is Al _ 2SiO _ 4 (f, OH) _ 2, which can contain trace elements Li Be and Ga, and pink topaz can contain Cr. Oblique crystal system, biaxial crystal, positive light The common crystal form is columnar with longitudinal stripes on the cylindrical surface. Common colors are colorless, light blue, blue, yellow, pink, brownish red and green. This kind of glass is shiny and transparent. A set of perfect cleavage; Mohs hardness 8; The density is about 3.53g/cm3, and the refractive index is1.619 ~1.627.

Polychromaticity is weak to moderate, and changes with color change. Generally, the long-wave ultraviolet fluorescence is orange and green, and the short-wave ultraviolet fluorescence is weak. No intrinsic absorption spectrum. Two-phase and three-phase inclusions, two or more immiscible liquid inclusions, mineral inclusions and negative crystals are common in crystals. Mainly produced in granite pegmatite and greisen. The origin is distributed all over the world, including Brazil, Myanmar, the United States, Sri Lanka and so on.

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