Kolwezite
Current inventory:  0 gems
 

  
Kolwezite is named for its occurrence at Kolwezi, Democratic Republic of Congo (Zaïre) where it was discovered at the Musonoi Mine.

Discovered in 1980; IMA status: Valid (IMA Approved 1980)

Chemistry

Chemical Formula:

(Cu,Co)₂(CO₃)(OH)₂

Copper Cobalt Carbonate Hydroxide

Molecular Weight:

218.07 gm

Composition:

Cobalt

17.84 %

Co

22.68 %

CoO

Copper

39.05 %

Cu

48.88 %

CuO

Hydrogen

0.92 %

H

8.26 %

H₂O

Carbon

5.51 %

C

20.18 %

CO₂

Oxygen

36.68 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Carbonates

Strunz 8th Ed. ID:

5/C.01-50

Nickel-Strunz 10th Ed. ID:

5.BA.10

5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H₂O
A : With Cu, Co, Ni, Zn, Mg, Mn

Related to:

Rosasite Group (synonym: Malachite-Rosasite Group). Structurally related to Malachite.

Members of Group:

Rosasite Group: Glaukosphaerite, Kolwezite, Mcguinnessite, Parádsasvárite, Pokrovskite, Rosasite, Zincrosasite 

Varieties:

None

Synonyms:

IMA1979-017, Koluezite

Crystal Data

Crystallography:

Triclinic 

Crystal Habit:

In spherical aggregates, to 1 cm, and microcrystalline crusts. 

Twinning:

None

Physical Properties

Cleavage:

None

Fracture:

n/a

Tenacity:

Brittle

Moh's Hardness:

~4.0

Density:

3.97 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Blackish brown to pale beige, greenish

Transparency:

Semitransparent, translucent to subopaque

Luster:

Vitreous

Refractive Index:

1.688 - 1.900  Biaxial

Birefringence:

0.212

Dispersion:

Weak, r > v

Pleochroism:

None

Occurances

Geological Setting:

An uncommon secondary mineral in the oxidation zone of some Cu–Co hydrothermal ore deposits.

Common Associations:

Cobaltian Calcite, Cobaltian Dolomite, Cobaltian Malachite, Heterogenite

Common Impurities:

None

Type Locality:

Musonoi Mine, Kolwezi, Kolwezi District, Katanga Copper Crescent, Katanga (Shaba), Democratic Republic of Congo (Zaïre)

Year Discovered:

1980

View mineral photos:

Kolwezite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Kolwezite is a rare mineral that occurs in some oxidized copper-cobalt ore deposits. It is named for its occurrence at the famous mines at Kolwezi, Democratic Republic of Congo (Zaïre) where it was discovered at the Musonoi Mine. Kolwezite belongs to the Rosasite Group of minerals that also includes Perovskite and Rosasite among others. The Rosasite Group is a group of metal hydroxide carbonate minerals. Kolwezite is similar to the much more common Malachite. One of the main differences between the two is that Kolwezite contains a significant percentage of cobalt in place of some of the copper contained in Malachite.

Kolwezite crystals are too small for faceting but very attractive and collectible as mineral specimens. The crystals are found as blackish brown to pale beige, but most often as greenish radiating spherical aggregates and microcrystalline crusts. The most desirable Kolwezite specimens often resemble green cotton balls on bright pink Cobaltoan Calcite (as pictured above). There are only a few localities for Kolwezite worldwide.

Distribution: from the Type Locality at the Musonoi and Kamoto Cu–Co mines, near Kolwezi, and the Mupine, and Mashamba West mines, Katanga Province, Congo (Zaire). In Germany at the Prangenhaus Quarry, Rohdenhaus, Wülfrath, Niederberg area, North Rhine-Westphalia. In Greece at the Kamariza Mines (Kamareza Mines), St. Constantine, Lavrion District Mines, Lavrion District, Attikí Prefecture. In the USA at the Tuckerville prospects, Hinsdale County, Colorado.
 

  
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