Heubnerite is variety, belonging to the Wolframite mineral that is rich in manganese, and the last member in the Wolframite family. It is not separately classified, but it is occasionally grouped as Wolframite. When the iron content increases, it is likely to deepen the black coloration, increase in its density and reduce its transparency.
Derivation of Name
In the year 1865, Eugene N. Riotte, a native of Elberfield, Germany, named this mineral after Friedrich Adolph Hubner (May 17th, 1830), of Koenigsberg, East Prussia (Germany), he was a German mining Engineer and also a metallurgist from Freiberg of Saxony.
Huebneriti is found in the hydrothermal veins where the temperature is extreme and as granites that are pneumatolytically (Wiki describes Pneumatolysis is the alteration of rock or mineral crystallization affected by gaseous emanations from solidifying magma. The term was coined by Robert Bunsen in 1851), modified granites that give greisens (Wiki explains it thus_ Greisen is a highly altered granitic rock or pegmatite. Greisen is formed by self-generated alteration of granite): in the deposits of alluvial, granite pegmatites and alluvial deposits.
Huebnerite is hardly made into gemstones.
The sources where it likely occurred are China, Nanling range; Northern Carolina, France, Colorado and Idaho; USA; Peru, Russia, Bolivia and England.
Hubnerite occurs in a different series of mineral, known as Ferberit (FeWO4). Hubnerite is the last member in the series that is rich in manganese, whereas Ferberite is the last member of the series, rich in iron. The name of the series is Wolframite, functional to specimens that are not clearly distinguished and those that fall in between the two minerals. The majority of the specimens obtained naturally are placed within 20 to 80 % in the series range, they are expressed as wolframites, (FeMn) WO4. These are called as Hubnerite only if their purity in manganese exceeds 80%. Even though Hubnerite is more general than ferberite, it is not as general as Wolframite. The differences of Hubnerite and ferberite from Hubnerite is in their iron content. The color of Hubnerite is normally light, having a still lighter streak, its transparency is greater and density lesser, whereas Ferberite is more towards the blackish side of color, having black streaks, it is opaque and its luster submetalic, its magnetic property is weak. The characteristics of Wolframite are between these two.
Varying from yellow to brown.
4 to 4.5