Wolfeite
Wolfeite is a rare phosphate mineral with the chemical formula (Fe²⁺,Mn²⁺)₂(PO₄)(OH). It belongs to the monoclinic crystal system and is classified in the Strunz system as 8.BB.15 and in the Dana system as 41.6.3.1. The mineral typically exhibits a vitreous to subvitreous luster and is usually greenish to yellowish in color. It has a hardness of approximately 4.5 on the Mohs scale and a specific gravity around 3.4. Wolfeite is a member of the phosphates, arsenates, and vanadates group, and its composition reflects a mixture of iron and manganese in the +2 oxidation state.
Composition
- FeIron49.9%
- OOxygen35.8%
- PPhosphorus13.8%
- HHydrogen0.5%
Overview
Wolfeite is a rare phosphate mineral with the chemical formula (Fe²⁺,Mn²⁺)₂(PO₄)(OH). It belongs to the monoclinic crystal system and is classified in the Strunz system as 8.BB.15 and in the Dana system as 41.6.3.1. The mineral typically exhibits a vitreous to subvitreous luster and is usually greenish to yellowish in color. It has a hardness of approximately 4.5 on the Mohs scale and a specific gravity around 3.4. Wolfeite is a member of the phosphates, arsenates, and vanadates group, and its composition reflects a mixture of iron and manganese in the +2 oxidation state.
Etymology
Wolfeite is named after Caleb W. Wolfe, an American mineralogist. The mineral was recognized as a valid species and is considered grandfathered by the IMA, meaning it was described before the IMA's establishment in 1959.
How to recognize it
Wolfeite can be identified by its greenish to yellowish color and vitreous luster. It has a hardness of about 4.5 on the Mohs scale, which is relatively soft for a phosphate mineral. Its specific gravity is approximately 3.4, which is moderate. The streak is typically white or pale. Due to its rarity and similar appearance to other phosphates, it may be confused with other greenish phosphate minerals.
Trivia
Wolfeite is notable for its unique chemical composition, which includes both iron and manganese in the +2 oxidation state. It is a rare mineral, with few known localities. Its classification in the phosphate group reflects its phosphorus content, which is uncommon in many other mineral classes.