Basic properties and identification of turquoise

The beauty of turquoise has been running through human history for thousands of years. Today, in many parts of the world, turquoise is also a sacred gem. In most parts of the world, turquoise is widely used in decorations. Above the artwork, it is an important part of the world's many gemstone species. Here is a brief introduction to the basic standards of turquoise in the national gem identification.

English name: turquoise

Mineral (rock) name: turquoise

Chemical composition: CuAl6(PO4)4(OH)8.5H2O

Crystallized state: usually in the form of a block or skin, an oversized cryptocrystalline aggregate

Common colors: light to medium blue, green blue to green, often with spots, mesh or dark mineral impurities.

Gloss: waxy luster to glass luster.

Cleavage: None.

Mohs hardness: 5-6

Density: 2.76 (+0.14, -0.36) g/cm3

Photographic characteristics: heterogeneous aggregates.

Polychromism: None.

Refractive index: 1.610-1.650, the spot method is usually 1.61.

Birefringence: The aggregate is unmeasurable.

UV fluorescence: long wave: no weak, green yellow; short wave: none.

Absorption spectrum: Occasionally 420, 432, 460 nm medium to weak absorption band.

Magnification check: common dark matrix.

Special optical effects: not seen.

Optimized treatment: Dip wax: The surface is impregnated with wax to seal the tiny holes. Hot needle melted wax, low density, enlarged inspection.

Plastic filling: Inject colored or colorless plastic on the turquoise surface to make the surface smooth and bright. The density is low, the hot needle can dissolve the organic matter, and the organic matter is determined by infrared spectroscopy, and the inspection is carried out.

Filling treatment: Fill the holes with a metal-filled epoxy resin or the like. Magnification check, hot needle, infrared spectrum.

Dyeing treatment: Dyeing with materials such as black liquid shoe polish, mimicking the dark matrix. Zoom in and the hot needle melts.

Important identification items: density, refractive index, absorption spectrum, magnification inspection, infrared light.