Grandidierite
Mineral Group: borosilicate Group
Key Properties
| Property | Value |
|---|---|
| Mohs Hardness | 7.5 (7.5) |
| Typical Size | 0.1-5 carats (commercial: 0.25-2 carats; faceted stones over 3 carats are rare) |
| Typical Price Range | $5,000-30,000+ per carat (commercial: $10,000-20,000; faceted stones extremely rare) |
| Rarity Level | Singular Occurrence |
| Availability Level | Museum Grade Rarity |
| Availability Driver | Limited Deposits |
| Investment Appropriateness | Speculative Collector Gems |
Detailed Descriptions
Rarity Description: A very rare blue-green mineral with limited localities; collector-grade gems are scarce.
Availability Description: Sporadic offerings to collectors and museums; rarely seen in retail jewelry markets.
Investment Description: Rare blue-green gem with growing recognition; limited faceted material; strong appreciation in recent years; small but expanding collector market.
Colors
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Investment Ranking Calculation
The composite score of 78.75 is calculated using a weighted formula:
- Geological Rarity (25%): 100 points
- Market Availability (25%): 100 points
- Investment Appropriateness (25%): 50 points
- Hardness (12.5%): 45 points
- Price Range (12.5%): 85 points
Formula: (100 × 0.25) + (100 × 0.25) + (50 × 0.25) + (45 × 0.125) + (85 × 0.125) = 78.75
BULLISH
78.75
Score Components
Geo rarity
100
Mkt availability
100
Invest Appr
50
hardness
45
price
85