Ferberite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameFerberite
Chemical FormulaFeWO4
Mohs Hardness4
Crystal Systemmonoclinic
Lustervitreous
Streak Colordark reddish brown to brownish black
Cleavageperfect on {010}
Fractureuneven to subconchoidal
Specific Gravity7.4
Colorsblack, brownish-black, dark gray
Transparencyopaque
Type LocalityPanasqueira, Covilhã, Castelo Branco District, Portugal
Mineral GroupTungstates
Usesore of tungsten, collector
Associated Mineralsquartz, muscovite, cassiterite, arsenopyrite, pyrite, chalcopyrite, fluorite, apatite, topaz
Rarityuncommon
Description
This image features a sharp, blocky, black ferberite crystal exhibiting a submetallic luster, likely showing distinct crystal faces and possibly some striations.
Geological Context
Ferberite is typically found in high-temperature hydrothermal veins, often associated with granitic intrusions, and can occur in greisen and pegmatite deposits.
