Covellite Value, Price, and Jewelry Information
Although covellite has attractive blue colors and shows iridescence, this rare mineral is difficult to cut. You can scratch it with a fingernail! As cut gems, they're strictly curiosities for collectors.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Crystallography||Hexagonal. Crystals are tabular; also massive and cleavages.|
|Colors||Light to dark indigo blue; purplish; commonly iridescent, yellow and red.|
|Luster||Submetallic to resinous.|
|Hardness||1.5 - 2|
|Cleavage||Perfect and easy 1 direction|
|Transparency||Opaque, except in thin slivers.|
|Pleochroism||Strong, but visible only in very thin sheets. Deep blue to pale blue.|
|Optics||o = 1.45, e = 2.629. Uniaxial (+).|
|Etymology||After Niccolo Covelli, the Italian chemist who discovered the mineral.|
|Occurrence||Secondary enrichment zones of copper mines.|
|Inclusions||Pyrite and chalcopyrite veins.|
Cut covellites (or covellines) have no great value. With hardness ranging from 1.5 to 2, coins and fingernails could scratch these gems. Although gem cutters have cut cabochons from this material, covellite would make a challenging jewelry stone.
“Pink Fire” Quartz
Covellite leaves a shining, gray-black streak. (Usually, metallic gems, like this copper sulfide, have a colored streak). You’ll likely have no occasion to conduct a destructive streak test for identification purposes. However, if you want to see firsthand one of the few gems to leave a non-white, non-colorless streak, use a small spare piece or test a piece on an inconspicuous spot.
Covellites have some unusual structural and electrical properties of interest to science and industry. This mineral is a naturally occurring superconductive material. Not surprisingly, researchers have synthesized it, but use of this synthetic material for jewelry or other adornment is unknown (and unlikely, given its softness).
The type locality for this gem is the infamous Mount Vesuvius. Italy, principally Sardinia, remains an important source of gem-quality material.
Other notable sources include the following:
- United States: Alaska; California; Colorado; Butte, Montana; South Dakota; Utah; Wyoming.
- Argentina; Australia; Bosnia-Herzegovina; Germany; New Zealand; Philippines; Serbia.
Gem cutters generally cut cabochons from massive or foliated material. As a result, the cabs can be very large, up to several inches long.
You’re more likely to find covellites, if at all, in mineral collections than in jewelry collections. Jewelry use isn’t recommended. Consult our Gemstone Jewelry Cleaning Guide for care recommendations.