Sphalerite

saf-ahyuh r

With greater dispersion than diamond, sphalerite is an intriguing, yet challenging, gem. Known primarily to collectors due to its lack of hardness, sphalerite can try the patience of even the most highly skilled lapidaries who dare to fashion it into a finished gem. Not only is it extremely soft, it also has perfect cleavage, in six directions, making it extremely difficult to cut and polish! Add in the fact that it's a brittle gem, and you have an idea of the challenge that awaits its potential cutter. When that talented lapidary is, however, able to complete his task with a fashioned gem, the results are more than worth the lapidary's efforts!

Sphalerite Polished
Sphalerite Classification
Common Name Sphalerite
Species Sphalerite
Sphalerite Optical Properties
Transparency Transparent - Opaque
Dispersion Strength: Extreme Fire Value: 0.156
Refractive Index Over The Limit 2.369-2.500
Optic Character NA
Optic Sign NA
Polariscope Reaction Singly Refractive (SR)
Fluorescence SWUV: Inert to yellow, orange or strong orange-red
LWUV: Inert to yellow, orange or strong orange-red
Pleochroism None
Sphalerite Characteristic Physical Properties
Hardness 3.5-4
Streak Yellowish To Light Brown
Specific Gravity 3.900-4.100 Typical:4.050
Toughness Poor
Inclusions Sphalerite is frequently color zoned and has very strong dispersion.
Luster Adamantine, Submetallic, Resinous, Greasy
Fracture Conchoidal, Uneven
Cleavage Perfect, in six directions
Sphalerite Chemistry & Crystallography
Chemical Name zinc iron sulfide
Chemical Formula (Zn,Fe)S
Crystal System Cubic
Chemistry Classification Sulfide

Sphalerite Colors

  • Black Sphalerite Black
  • Yellow Sphalerite Yellow
  • Red Sphalerite Red
  • Orange Sphalerite Orange
  • Multi-color Sphalerite Multi-color
  • Green Sphalerite Green
  • Gray Sphalerite Gray

Alternate Names

Cleiophane, Marmatite, Zinc Blende

Countries of Origin

United States of America (the); Republic of Kosovo; Sri Lanka; Madagascar; Spain; Canada; Unknown; China; Russian Federation (the); Mexico; Bulgaria; Germany; United Kingdom of Great Britain and Northern Ireland (the)

Care

Sphalerite is a very soft stone, so be mindful of scratching. It is generally not suited for jewelry use.

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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.