Rickardite Locality: Good Hope Mine, Vulcan District, Gunnison County, Colorado ( Locality at mindat.org ) A very metallic, bright specimen showing lathe-shaped crystals of tellurium admixed with sparkling rickardite in microcrystals around it. Rickardite is a SUPER RARE copper telluride, first discovered here in the early 1900s. This specimen, formerly #17583 in the AMNH collection, surely dates to those early days. It comes with an AMNH label showing it was a gift from an FJ Arkins (I do not know of him). Good Hope Mine, Vulcan District, Gunnison Co., Colorado is the TYPE LOCALE. Ex AMNH exchanged into the collection of dealer/collector Lawrence Conklin. 2.7 x 2.1 x 1.4 cm. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Rickardite
A copper telluride described from Colorado's Good Hope mine, named for mining engineer Thomas Rickard.
Intro adapted from Wikipedia (CC BY-SA).
Rickardite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Cu₃₋ₓTe₂.
It crystallizes in the tetragonal crystal system (space group P4/nmm).
Key properties: Mohs hardness 3.5; specific gravity 7.54; Metallic luster.
IMA symbol Rkd, grandfathered status — known before the IMA’s founding, named in 1903.
A late-stage mineral of low-temperature hydrothermal origin in some Te-bearing mineral deposits.
It is found associated with Vulcanite, tellurium, cameronite, petzite, sylvanite, berthierite, pyrite, arsenopyrite, bornite.
In honor of Thomas Arthur Rickard (1864–1953), mining engineer and Editor of the Engineering and Mining Journal, New York and London.