Dumortierite
What is Dumortierite?
Dumortierite is a fibrous, typically blue, rarely violet or green, mineral. It is a nesosilicate of aluminum that crystallizes in the orthorhombic crystal system. It is often found in metamorphic rocks rich in aluminum and is sometimes used as a gemstone.
Optical Properties
- Refractive Index
- 1.672-1.685
- Birefringence
- 0.016
- Pleochroism
- Strong, blue to colorless
- Optical Character
- biaxial (-)
- Dispersion
- 0.020
Dumortierite Market Value Calculator
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Dumortierite Localities Map
See where Dumortierite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Map preview
North ZoneCentral RidgeSouth Basin
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Quick Facts
Physical Properties
- Color
- Blue, violet, green, colorless, pink, brown
- Hardness (Mohs)
- 7
- Density
- 3.26 to 3.41 g/cm³
- Streak
- Blue, colorless
Chemical Properties
- Chemical Formula
- Al7BSi3O18(OH)3
- Elements
- Silicon, aluminum, boron, oxygen, and hydrogen
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