Cronstedtite
A variety of Minerals
What is Cronstedtite?
Cronstedtite is a complex iron silicate mineral belonging to the serpentine group of minerals. Its chemical formula is Fe2Fe(Si,FeO5)(OH)4. It was discovered in 1821 and named in honor of Swedish mineralogist Axel Fredrik Cronstedt (1722–1765). It has been found in Bohemia in the Czech Republic and in Cornwall, England. Cronstedtite is a major constituent of CM chondrites, a carbonaceous chondrite group exhibiting varying degrees of aqueous alteration. Cronstedtite abundance decreases with increasing alteration.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Cronstedtite 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.
Cronstedtite Localities Map
See where Cronstedtite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
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Quick Facts
Physical Properties
- Color
- Black, dark brown-black, green-black
- Hardness (Mohs)
- 3.5
- Density
- 3.34 - 3.35 g/cm³
- Streak
- Dark olive-green
Chemical Properties
- Chemical Formula
- Fe2+2Fe3+((Si,Fe3+)2O5)(OH)4
- Elements
- Fe, H, O, Si
Also Known As
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Cronstedtite FAQs
How do I identify Cronstedtite?
Cronstedtite can be identified by its hardness of 3.5 on the Mohs scale, Black color. Look for these key characteristics when examining specimens.
What color is Cronstedtite?
Cronstedtite typically appears in Black, dark brown-black, green-black. Color can vary depending on impurities and formation conditions.
How hard is Cronstedtite?
Cronstedtite has a hardness of 3.5 on the Mohs scale. This gives it moderate hardness.
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