wolframite

views updated May 08 2018

wolframite Ore mineral for tungsten, with the formula (Fe,Mn)WO4; sp. gr. 7.0–7.5; hardness 5.0–5.5; monoclinic; grey-black to brownish-black; brownish black streak; metallic lustre; crystals normally tabular, prismatic, often bladed, also occurs granular and massive; cleavage perfect quartz; occurs in high-temperature hydrothermal veins, quartz veins, and pegmatites, associated with granitic rocks, with cassiterite, arsenopyrite, tourmaline, scheelite, galena, sphalerite, and quartz.

wolframite

views updated May 23 2018

wolframite (iron-manganese tungstate) Black to brown mineral, (Fe,Mn)WO4. It is the chief ore of the metal tungsten. It occurs as crystals in the monoclinic system or as granular masses. It is found in quartz veins and pegmatites associated with granitic rocks and also in hydrothermal veins. Hardness 5–5.5; r.d. 7–7.5.