Colemanite
A variety of Minerals
What is Colemanite?
Colemanite is an important boron ore, and is usually colorless to white, brown or yellow. It is used in the production of heat resistant glass and is a source of borax, a cleaning agent and industrial chemical. Colemanite is fragile and gem cutters rarely work these stones. They are better suited for gemstone collectors.
Uses & Applications
Colemanite is an important ore of the element boron, which can be used in pyrotechnics and rocket fuel. Additionally, it can be used to create flame and heat resistant materials, including glass. Colemanite is also processed to be used in cosmetics and medicines.
Optical Properties
- Refractive Index
- 1.584-1.615
- Birefringence
- 0.028-0.030
- Pleochroism
- None
- Optical Character
- Biaxial positive
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Colemanite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Colemanite Localities Map
See where Colemanite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Colourless, white, yellowish, grey, colourless in transitted light
- Hardness (Mohs)
- 4.5
- Density
- 2.422 g/cm³
- Streak
- White
- Luster
- Vitreous, Adamantine
- Crystal System
- Monoclinic
Chemical Properties
- Chemical Formula
- Ca[B3O4(OH)3] · H2O
- Elements
- B, Ca, H, O
Also Known As
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Colemanite FAQs
How do I identify Colemanite?
Colemanite can be identified by its hardness of 4.5 on the Mohs scale, Colourless color, Vitreous, Adamantine luster, Monoclinic crystal system. Look for these key characteristics when examining specimens.
What color is Colemanite?
Colemanite typically appears in Colourless, white, yellowish, grey, colourless in transitted light. Color can vary depending on impurities and formation conditions.
How hard is Colemanite?
Colemanite has a hardness of 4.5 on the Mohs scale. This gives it moderate hardness.
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