Synthetic Turquoise


Properties of Synthetic Turquoise:
Chemical Composition Copper aluminum phosphate hydroxide hydrate with traces of Ca, Si and Mg; no Fe
Hardness 4 1/2 - 4 3/4
Specific Gravity 2.56 - 2.75; closer 2.75
Transparency Semi translucent to opaque
Refractive Index 1.598
R.I. Range ± 0.01
Optical Characteristic Doubly refractive, but only a single reading seen on refractometer; opaque
Color Blue
Fluorescence X-Ray - None ; SW UV -Very faint yellow green; LW UV - Moderate greenish-blue
Spectrum None to very very weak
Inclusions No characteristic inclusions

TESTING :

Natural turquoise of the same intensity of color and properties shows an absorption spectrum whereas synthetic turquoise does not. Microspheres which are characteristic structural features of synthetic turquoise under high magnification are not present in natural turquoise, (Note: The so-called "synthetic turquoise" distributed by Gilem SA, Geneva, Switzerland, may not be a true synthetic turquoise because the tiny spheres are held together by a binding agent.)



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