It should not be difficult to find numerous small, faceted huebnerite gems (also hübnerite or hubnerite) among larger collections. Certainly ample material exists to cut a number of such gems, although they are rarely offered for sale.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Crystallography||Monoclinic; crystals prismatic; flattened; tabular, often striated in direction of elongation. Often in crystal groups, radiating or parallel aggregates. Commonly twinned.|
|Colors||Brownish black, yellowish to reddish brown, red. Streak yellowish, reddish brown, blackish to greenish gray. Sometimes color banded; sometimes tarnished iridescent.|
|Luster||Submetallic to resinous.|
|Hardness||4-4.5 (increases with iron content).|
|Specific Gravity||7.12-7.18 (increases with iron content).|
|Cleavage||Perfect in 1 direction.|
|Stone Sizes||Huebnerite is transparent, and opacity increases with iron content. Material suitable for faceting occurs in Peru, and stones of several carats in weight may be cut but tend to be dark.|
|Formula||MnWO4 Series to Ferberite: FeWO4.|
|Pleochroism||Varies with locality and iron content: bright yellow/orange-red/orange-red; greenish-yellow/ orange-red/bright red; olive green/brick-red/dark red.|
Optics: a = 2.17-2.20; β= 2.22; γ= 2.30-2.32. Biaxial (+).
Occurrence: High-temperature hydrothermal ore veins; quartz veins in or near granitic rocks; Many localities in western United States (Colorado: Idaho; Nevada; New Mexico; Arizona; South Dakota).
France; Czechoslovakia; Australia.
Pasto Bueno, Peru: transparent crystals.
Comments: It should not be difficult to find numerous small faceted huebnerites among larger gemstone collections. Certainly ample material exists to cut a number of such gems, although they are rarely offered for sale.
Name: After Adolph Hubner, a metallurgist from Freiburg, Saxony (Germany). Ferberite was named after Rudolph Ferber, of Gera, Germany.