Sillimanite

Mineral Group: Sillimanite Group

Key Properties

Property Value
Mohs Hardness 7.0 (6.5-7.5)
Typical Size 0.5-10 carats (commercial: 1-5 carats; cat's eye varieties typically smaller)
Typical Price Range $50-300 per carat (commercial: $80-200; cat's eye varieties higher)
Rarity Level Limited Occurrence
Availability Level Limited Supply
Availability Driver Limited Deposits
Investment Appropriateness Non-Investment Gems

Detailed Descriptions

Rarity Description: A fibrous aluminosilicate that is occasionally cut as a collector gem; uncommon.

Availability Description: Mainly of interest to collectors; small quantities appear through specialist mineral and gem dealers.

Investment Description: Small collector market; cat's eye varieties have limited appeal; no significant investment potential due to minimal demand.

Colors

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Investment Ranking Calculation

The composite score of 40.0 is calculated using a weighted formula:

  • Geological Rarity (25%): 65 points
  • Market Availability (25%): 65 points
  • Investment Appropriateness (25%): 5 points
  • Hardness (12.5%): 25 points
  • Price Range (12.5%): 25 points

Formula: (65 × 0.25) + (65 × 0.25) + (5 × 0.25) + (25 × 0.125) + (25 × 0.125) = 40.0

BEARISH
40.0

Score Components

Geo rarity
65
Mkt availability
65
Invest Appr
5
hardness
25
price
25