Zoisite · Violet-blue
Tanzanite
A thousand times rarer than diamond.
Certified · traceable origin
Typical size: 2 – 15 ct · Price on request
Specifications
- Mineral family
- Zoisite
- Composition
- Ca₂Al₃(SiO₄)₃(OH) : V
- Hardness (Mohs)
- 6 – 7
- Refractive index
- 1.691 – 1.700
- Crystal system
- Orthorhombic
- Colour
- Violet-blue with pleochroic flashes
- Typical origins
- Merelani, Tanzania (single source)
Specifications are general gemological references for the species; each stone is assessed and documented individually.
Origin & story
Tanzanite is found in only one place on Earth — the foothills of Kilimanjaro in Tanzania. Its velvety violet-blue, with flashes of purple, emerged only decades ago and captivated the world.
Because its source is finite, tanzanite grows rarer each year. SOMSTONE assesses stones for depth of colour, clarity, and the pleochroism that gives tanzanite its life.
Documentation
What to expect from a lab report
Where appropriate, stones are submitted to an independent gemological laboratory. A typical identification report records the fields below; values shown here are placeholders for illustration only and do not describe a specific stone.
Illustrative only. Not an actual certificate. Reports are issued by independent laboratories on a per-stone basis.
Sample — illustrative layout
Specifications · Tanzanite
Report no. SAMPLE-000000
Date DD · MM · YYYY
- Identification
- Zoisite
- Variety
- Tanzanite
- Weight
- —.— ct
- Dimensions
- —.— × —.— × —.— mm
- Shape / cut
- —
- Colour
- Violet-blue with pleochroic flashes
- Transparency
- Transparent
- Origin opinion
- Subject to laboratory analysis
- Treatment
- Subject to laboratory analysis
- Comments
- Issued with stone-specific measurements and photographs.
Frequently asked
Buyer questions
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