Wolframite

Wolframite is one of the most highly sought after collector minerals. Good specimens of the tungsten ore wolframite are hard to find. It is mined mostly in quartz veins and areas with granite intrusions. It is heavy and has the ability to conduct heat. Wolframite is made up of iron, manganese, and tungsten oxide. It occurs as tabular or bladed crystals. Its color ranges from a lighter grey to a deep black, and its luster is sub-metallic.

Wolframite is the intermediate between ferberite and hübnerite. Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is not classified as an individual mineral species by the IMA. It is universally recognized as the wolframite mineral series, with the minerals Huebnerite (Manganese rich) and Ferberite (iron rich) being its end members. Wolframite sits closer to the middle of the series, as its manganese and iron content are generally more equal.  Wolframite is named for its tungsten content (wolfram
means tungsten in German) Ref. https://dictionary.cambridge.org/dictionary/german-english/wolfram

Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite. This mineral was historically found in Europe in Bohemia, Saxony, and Cornwall.