saf-ahyuh r

Zoisite is a mineral species in the epidote group. The most celebrated variety is its blue to violet occurrence, tanzanite, but other zoisite colors include red, pink (thulite), green and purple. Discovered in the early 19th century, zoisite was named after Baron von Zois, an Austrian scientist and mineral collector.

Zoisite Polished
Zoisite Classification
Common Name Zoisite
Species Zoisite
Zoisite Optical Properties
Transparency Transparent - Opaque
Dispersion Strength: Weak Fire Value: 0.021
Refractive Index 1.691-1.700
Birefringence 0.008-0.013
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: Inert
LWUV: Inert
Pleochroism Trichroic, (in green gems) strong green, yellow, and greenish brown
Zoisite Characteristic Physical Properties
Hardness 6-7
Streak White
Specific Gravity 3.100-3.450 Typical:3.350
Toughness Varies
Inclusions Zoisite is a type I clarity stone. Stones rarely needles, chromite inclusions, growth and etch tubes.
Luster Vitreous
Stability Good
Fracture Conchoidal, Uneven
Cleavage Perfect, in one direction, Good, in one direction
Zoisite Chemistry & Crystallography
Chemical Name calcium aluminum silicate hydroxide
Chemical Formula Ca2Al3(SiO4)3(OH)
Crystal System Orthorhombic
Chemistry Classification Silicate

Zoisite Colors

  • Colorless Zoisite Colorless
  • Gray Zoisite Gray
  • Purple Zoisite Purple
  • Orange Zoisite Orange
  • Pink Zoisite Pink
  • Red Zoisite Red
  • Blue Zoisite Blue
  • Brown Zoisite Brown
  • Green Zoisite Green
  • Yellow Zoisite Yellow

Countries of Origin

Tanzania, United Republic Of; Pakistan; French Polynesia


Normal, gentle handling, avoid high heat and acids.

Sisk Gemology Reference

Showcasing 200 gemstones in over 1,000 pages and accompanied by more than 2,000 photos, The Sisk Gemology Reference is a must-have in every collector’s library. Each comprehensive, three-volume set features state-of-the-art photography, detailed illustrations, and scientifically precise descriptions to create an entrancing experience for gemstone amateurs and afficionados alike.

Shop Now

Tim Matthews


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.