Achroite

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Achroite refers to the colorless variety of tourmaline. An elbaite tourmaline variety, these gems are very rare and especially prized by collectors.

Achroite Polished
Achroite Classification
Common Name Achroite
Species Tourmaline
Achroite Optical Properties
Transparency Transparent - Opaque
Dispersion Strength: Weak Fire Value: 0.017
Refractive Index 1.624-1.644
Tolerance:(+0.011/-0.009)
Birefringence 0.018- 0.020
Optic Character Uniaxial
Optic Sign Negative
Polariscope Reaction Doubly Refractive (DR)
Fluorescence SWUV: Inert
LWUV: Inert
Pleochroism None
Achroite Characteristic Physical Properties
Hardness 7-7.5
Streak White
Specific Gravity 3.000-3.260 Typical:3.060
Toughness Fair
Inclusions Achroite has liquid and gas inclusions that are long and thin, reflective gas-filled fractures and color zoning.
Luster Vitreous
Stability Very Good
Fracture Conchoidal, Uneven
Cleavage Poor
Achroite Chemistry & Crystallography
Chemical Name complex boro-silicate of Al, Mg and Fe
Chemical Formula Na(Li1.5Al1.5)Al6(Si6O16)(BO3)3(OH)3(OH)
Crystal System Trigonal
Chemistry Classification Silicate

Achroite Colors

  • Colorless Achroite Colorless

Countries of Origin

Afghanistan

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Tim Matthews

Author

Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.