Sugilite

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Sugilite belongs to a class of minerals known as silicates and is a member of the milarite group. A relatively recent addition to the realm of gemstones, sugilite was discovered in 1944 by a Japanese geologist, Ken-ichi Sugi. The mineral is named in his honor. The original find was a yellowish brown variety that was of no interest to the jewelry industry. It was not until 1979 that the first massive aggregates, exhibiting a rich purple color, were discovered in a South African manganese mine. This material was attractive and gained the attention of the gemstone industry. It is predominantly found in the form of cabochons of various shapes and sizes, but has also been used as a component in intarsia jewelry. It is sometimes carved into decorative objects and fashioned into beads.

Sugilite Polished
Sugilite Classification
Common Name Sugilite
Species Sugilite
Sugilite Optical Properties
Transparency Semitransparent - Opaque
Refractive Index 1.607-1.610
Tolerance:(+0.001/-0.002)
Birefringence 0.003
Optic Character Uniaxial
Optic Sign Negative
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: Inert
LWUV: Inert
Pleochroism None
Sugilite Characteristic Physical Properties
Hardness 5.5-6.5
Streak White
Specific Gravity 2.690-2.790 Typical:2.740
Toughness Good
Inclusions Sugilite might have banded appearance.
Luster Vitreous, Waxy
Fracture Granular
Cleavage None
Sugilite Chemistry & Crystallography
Chemical Name potassium sodium lithium iron manganese silicate
Chemical Formula (K,NA)(Na,Fe)2(Li2Fe)Si12O30
Crystal System Hexagonal
Chemistry Classification Silicate

Sugilite Colors

  • Purple Sugilite Purple

Alternate Names

Royal Azel, Royal Lavulite

Countries of Origin

Unknown; South Africa

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Tim Matthews

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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.