Bicolor Tanzanite

Physical Properties

Hardness: 6-7 Mohs; Color: Distinct blue and violet/pink zones; Luster: Vitreous; Crystal system: Orthorhombic; Cleavage: One perfect; Specific Gravity: 3.35.

Formation & Geological History

Formed in regional metamorphic environments where calcium-rich rocks were subjected to high heat and pressure, specifically within marble/quartzite layers during the Pan-African orogenic event (approx. 585 million years ago).

Uses & Applications

Primarily used as a gemstone in high-end jewelry (rings, pendants, earrings) and as a highly sought-after specimen for investment collectors.

Geological Facts

Tanzanite is 1,000 times rarer than diamonds because it is only found in a small 4km x 2km area near Mount Kilimanjaro. It is famous for its strong trichroism, showing blue, violet, and burgundy colors when viewed from different angles.

Field Identification & Locations

Identify by its pleochroism (color shifting) and specific gravity. It is only found in the Merelani Hills of Tanzania. Collectors look for 'fancy' colors or sharp bicolor zoning.

Identified on: 5/15/2026

Mode: Standard