Oldhamite
A variety of Minerals
What is Oldhamite?
Oldhamite is a calcium magnesium sulfide mineral with formula (Ca, Mg)S. Ferrous iron may also be present in the mineral resulting in the formula: (Ca,Mg,Fe)S. It is a pale to dark brown accessory mineral in meteorites. It crystallizes in the cubic crystal system, but typically occurs as anhedral grains between other minerals.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Oldhamite 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.
Oldhamite Localities Map
See where Oldhamite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Key Characteristics
Formation of Oldhamite
It was first described in 1862 for an occurrence in the Bustee meteorite, Gorakhpur, Uttar Pradesh, India. It was named for Irish geologist Thomas Oldham (1816–1878), the Director of the Indian Geological Survey. It occurs as an interstitial mineral phase between silicate minerals in enstatite chondrite and achondrite meteorites. It occurs in association with enstatite, augite, niningerite, osbornite, troilite, gypsum and calcite. It has been reported from a variety of meteorite locations around the world including the Allan Hills 84001 meteorite of Antarctica. It has also been reported from a slag occurrence in France and a coal deposit in Poland.
Quick Facts
Physical Properties
- Color
- pale brown to dark brown
- Hardness (Mohs)
- 4
- Density
- 2.589 g/cm³
Chemical Properties
- Chemical Formula
- (Ca,Mg)S
- Elements
- Ca, Mg, S
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Oldhamite FAQs
How do I identify Oldhamite?
Oldhamite can be identified by its hardness of 4 on the Mohs scale, pale brown to dark brown color. Look for these key characteristics when examining specimens.
What color is Oldhamite?
Oldhamite typically appears in pale brown to dark brown. Color can vary depending on impurities and formation conditions.
How hard is Oldhamite?
Oldhamite has a hardness of 4 on the Mohs scale. This gives it moderate hardness.
What is the formation of oldhamite of Oldhamite?
It was first described in 1862 for an occurrence in the Bustee meteorite, Gorakhpur, Uttar Pradesh, India. It was named for Irish geologist Thomas Oldham (1816–1878), the Director of the Indian Geological Survey. It occurs as an interstitial mineral phase between silicate minerals in enstatite chondrite and achondrite meteorites. It occurs in association with enstatite, augite, niningerite, osbornite, troilite, gypsum and calcite. It has been reported from a variety of meteorite locations around the world including the Allan Hills 84001 meteorite of Antarctica. It has also been reported from a slag occurrence in France and a coal deposit in Poland.
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