The Mineral krennerite
There are only few minerals that contain gold in their structure. The rare mineral Krennerite is one of them. Krennerite is a
polymorph of
Calaverite, and occurs in the same localities as Calaverite. They may even occur together on the same specimen. Krennerite was named in honor of Hungarian Mineralogist József Sándor Krenner (1839-1920), the curator of the Hungarian Mineral Museum.
Color
Brass-yellow to silver-white
Crystal System
Orthorhombic
Properties
Streak
Grayish yellow to gray |
Hardness
2.5 - 3 |
Transparency
Opaque |
Specific Gravity
8.0 - 8.6 |
Luster
Metallic |
Cleavage
1,1 |
Fracture
Conchoidal to uneven |
Tenacity
Brittle |
Crystal Habits
In elongated prismatic crystals, and in short tabular crystals. Crystals are almost always striated lengthwise, and are usually small and in parallel or platy groupings. Also grainy, massive, and as coatings and crusts.
Uses
Krennerite is a rare collector's mineral, with special value due to its gold content.
Noteworthy Localities
The
type locality where Krennerite was first described is Sacarîmb (Nagyág), Hunedoara Co., Romania. Other localities for this rare mineral include the Emperor Mine, Vatukoula, Viti Levu, Fiji; and the Cripple Creek District, Teller Co., Colorado.
Common Mineral Associations
Quartz, Calaverite, Sylvanite
Distingushing Similar Minerals
Can be very difficult to distinguish from Calaverite and other gold tellurides, though forms in different crystals and has perfect cleavage.