Tanzanite
Mineral Group: Zoisite Group
Key Properties
| Property | Value |
|---|---|
| Mohs Hardness | 6.5 (6-7) |
| Typical Size | 0.5-50+ carats (commercial: 1-15 carats; large clean stones available but expensive) |
| Typical Price Range | $300-2,000+ per carat (commercial: $600-1,200; finest vivid blue-violet $1,500-2,000+) |
| Rarity Level | Singular Occurrence |
| Availability Level | Museum Grade Rarity |
| Availability Driver | Limited Deposits |
| Investment Appropriateness | Emerging Investment Gems |
Detailed Descriptions
Rarity Description: Violet-blue zoisite found only in a small area near Mount Kilimanjaro (Tanzania); limited primary source.
Availability Description: Primary market supply comes from Tanzanian mining and licensed wholesalers; fine stones are allocated to top dealers and auctions.
Investment Description: Single-source gem from Tanzania with finite supply; strong market recognition and dealer network; investment-grade requires vivid blue-violet and good size; appreciation potential but supply risk.
Colors
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Investment Ranking Calculation
The composite score of 78.12 is calculated using a weighted formula:
- Geological Rarity (25%): 100 points
- Market Availability (25%): 100 points
- Investment Appropriateness (25%): 75 points
- Hardness (12.5%): 10 points
- Price Range (12.5%): 65 points
Formula: (100 × 0.25) + (100 × 0.25) + (75 × 0.25) + (10 × 0.125) + (65 × 0.125) = 78.12
BULLISH
78.12
Score Components
Geo rarity
100
Mkt availability
100
Invest Appr
75
hardness
10
price
65