The Mineral sperrylite
Sperrylite is a rare mineral composed primarily of the precious metal platinum. Aside from native
Platinum, Sperrylite is the only platinum
ore of any economic importance. It forms in highly lustrous crystals that can be very well-formed, making this mineral a novelty for collectors due to its value. Sperrylite is named after Francis Louis Sperry (1861-1906), a chemist who discovered this mineral at Sudbury, Ontario in 1889.
Properties
Streak
Dark gray to black |
Hardness
6 - 7 |
Transparency
Opaque |
Specific Gravity
10 - 11 |
Luster
Metallic |
Cleavage
3,3 |
Fracture
Conchoidal |
Tenacity
Brittle |
Crystal Habits
In cubes with modified octahedral faces, and less commonly octahedral with modified cubic faces. Crystals, which are never large, may be in grouped clusters or individually formed. Also in distorted crystal groups and irregular fractured crystal masses. Crystals often contain irregular surface cracks.
Uses
Sperrylite is an important ore of the precious metal platinum, and good crystals are highly valued by mineral collectors.
Noteworthy Localities
The original locality where Sperrylite was first identified is the Vermilion Mine, Denison Township, Sudbury District, Ontario. This famous locality still produces small lustrous crystals in the old mine dumps. Another well-known Sperrylite deposit in the Sudbury District is the Broken Hammer Deposit, Wisner Township, which produces crystals in very sharp form.
The largest and best-formed Sperrylite crystals come from the Talnakh deposit, near Noril'sk, Eastern-Siberian Region, Russia. Sperrylite is of economic value and mined for its platinum content at the Bushveld Complex, Limpopo Province, South Africa. In the U.S.,
waterworn crystals were found in
alluvial placer deposits at Mason Mountain, Macon County, North Carolina.
Distingushing Similar Minerals
Galena - Lower hardness, has perfect cleavage.