• Chemistry: (Cu, Co)2CO3(OH)2, Copper Cobalt Carbonate Hydroxide.
  • Class: Carbonate
  • Group: Rosasite
  • Uses: A very minor ore of copper and cobalt, and as mineral specimens.
  • Specimens

Kolwezite is a rare mineral that is a similar mineral to the much more common and well-known mineral malachite. Malachite's formula is Cu2CO3(OH)2. Kolwezite contains a significant percentage of cobalt in place of some of the copper in malachite.

Cobalt and copper are two very strong coloring agents. Unfortunately, kolwezite is perhaps too strongly colored and is commonly black. It was only identified in the past fifteen years making it a rather "young" mineral in the mineral world. It is named for the famous mines at Kolwezi, Shaba, Zaire from where it was first discovered and from where many new and rare minerals are found.


  • Color is black, green to brown.
  • Luster is
  • Transparency is translucent.
  • Crystal System is triclinic; bar 1
  • Crystal Habits include prismatic to acicular crystal sprays and crusts.
  • Hardness is 4.
  • Specific Gravity is 4.0 (slightly heavy)
  • Associated Minerals include malachite, siderite, cobaltian calcite and sphaerocobaltite.
  • Notable Occurrences are limited to Kolwezi area of Shaba, Zaire.
  • Best Field Indicators are color, locality, density and hardness.
KOLWEZITE specimens:
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KOLWEZITE specimen kol-1
$ 75.00
Dims: 2.3" x 2.2" x 1.9" (5.8 x 5.6 x 4.8 cm)
Wt: 5.26 oz. (149.1 g)
Kisenge Mine, Zaire
A small crust and several loose clusters of Kolwezite rest on the host rock of this African specimen. The clusters are made up of sprays of acicular, needlelike crystals that are in generally good condition and do not exceed 3 mm in length. Some of these clusters also seem to have banded together to form 2 flat platelets that extend upwards from the sphaerocobaltite bed on which they rest. These platelets have a suspiciously hexagonal-looking shape. All of the formations that the Kolwezite takes seem to be green-colored but have a dirty pale-brown coloration that covers them. The sphaerocobaltite bed consists of dozens of small, pale pink scalenohedral crystals that are mostly covered, but show a bright, vitreous luster, transparence, and excellent clarity. They are quite small, though, not exceeding 4 mm in length. This bed rests on a base rock that appears to be a mixture of calcite, quartz, more sphaerocobaltite, and some decayed chrysocolla.
no photo
kol-1 ($ 75.00)
Kisenge Mine, Zaire
KOLWEZITE specimen kol-2
$ 69.00
Dims:2.6x2.3x1.1" (6.6x5.8x2.8 cm)
Wt: 4.6oz. (131g)
Mashamba West Mine, Shaba prov., Zaire
A limestone matrix covered on one surface with cobaltian calcite forms the host for several nodules of kolwezite on this specimen. Several of the kolwezite nodules are damaged, exposing a dark greenish-black interior. Were it not for this, they might easily be mistaken for malachite. The back of this specimen has been sawed,revealing small vugs of cobaltian calcite. Nothing can be seen of kolwezite's monoclinic form on this specimen, but this is not really surprising. These rounded nodules are the norm for this species.
no photo
kol-2 ($ 69.00)
Mashamba West Mine, Shaba prov., Zaire


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