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Gemstones 250x250

The Mineral covellite

Covellite on Pyrite Matrix

Covellite is a copper mineral that exhibits a unique iridescence, with strong metallic blue and sometimes purple colors. Iridescent Covellite is highly prized among collectors, especially when in rare crystallized form. Covellite is named after Niccolo Covelli, an Italian mineralogist who first discovered this mineral.

Chemical Formula

CuS 

Color

Dark metallic-blue to dark gray. Highly iridescent bright blue; sometimes also purple, red, and yellow.

Crystal System

Hexagonal

Properties

Streak
Dark gray to black
Hardness
1.5 - 2
Transparency
Opaque
Specific Gravity
4.6 - 4.8
Luster
Metallic
Cleavage
1,1
Fracture
Uneven
Tenacity
Brittle but slighty sectile. Thin flakes are flexible but not elastic.

Crystal Habits

Crystals, which are uncommon, are mostly in thin tabular hexagonal plates. They are usually bladed and doubly terminated. Most often platy, grainy, foliated, as coatings, in veins, and massive.

3D Crystal Atlas

Additional Information

Composition
Copper sulfide, sometimes with some iron
In Group
Sulfides; Simple Sulfides
Striking Features
Iridescent color and habits
Environment
In hydrothermal replacement ore deposits and in skarns.
Rock Type
Igneous, Sedimentary, Metamorphic

Uses

Brightly colored Covellite is used as a collector's mineral. Covellite is a minor ore of copper in copper deposits.

Noteworthy Localities

Some of the finest Covellite, in thin platy crystal stacks, came from the Calabona Mine, Alghero, Sardinia, Italy. Colorful foliated crystals have come from the Bor District, Serbia. In the U.S., the locality of Butte, Silver Bow Co., Montana, is perhaps the best-known locality for this mineral. Covellite clusters over three feet in length have been recovered at the Leonard mine in Butte. Aesthetic masses and think platy crystals of Covellite have come from the Summitville District, Rio Grande Co., Colorado.

Common Mineral Associations

Chalcopyrite, Bornite, Pyrite, Chalcocite

Distingushing Similar Minerals

Chalcopyrite and Bornite both can be confused with Covellite, but these both have a greater hardness. Their iridescence is also not usually as distinctively blue as Covellite.


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