Quantcast

The Mineral malachite

Russian Malachite Slab

Malachite is a popular mineral with its intense green color and beautiful banded masses. The banded specimens are formed by massive, botryoidal, reniform, and especially stalactitic Malachite that are dense intergrowths of tiny, fibrous needles. Dense banded specimens are often sliced and polished to bring out their beautiful coloring. The bands may consist of concentric rings with interesting patterns; such specimens are highly sought after. These concentric banded specimens are most commonly from African sources. Polished, banded Malachite has been carved into ornaments and worn as jewelry for thousands of years, and in some ancient civilizations it was thought to be a protection from evil when worn as jewelry.

Malachite is generally found together with blue Azurite, and sometimes the two may occur admixed or banded together, forming what is commonly known in the gem and mineral trade as "Azure-Malachite". Malachite may also replace Azurite crystals, retaining the original Azurite shape but chemically altering it.

For additional information, see the gemstone section on Malachite.

Chemical Formula

Cu2CO3(OH)2

Color

Light to dark green, sometimes banded with darker and lighter shades of green, and sometimes sparkling.

Crystal System

Monoclinic

Properties

Streak
Light green
Hardness
3.5 - 4
Transparency
Opaque, although translucent in thin splinters
Specific Gravity
3.9 - 4.0
Luster
Vitreous, silky, or dull
Cleavage
1,1 - basal. Not usually discernible because crystals are tiny.
Fracture
Splintery
Tenacity
Brittle

Crystal Habits

Most common habit is as large crusts of microscopic crystals. Also occurs as bundles of thin long splinters. Large individual crystals are very rare and are usually pseudomorphs after Azurite or Cuprite. When they are not pseudomorphs, they are prismatic, tabular, re-entrant twins, and thin splinters. Also occurs acicular, radiating, reniform, botryoidal, as banded masses, earthy, stalactitic, tuberose, as thin wires, and as thin films coating other minerals.

3D Crystal Atlas

Additional Information

Composition
Basic copper carbonate
In Group
Carbonates
Striking Features
Green color, crystal habits, and association with Azurite
Environment
As a secondary mineral in the oxidation zone of copper deposits.
Rock Type
Sedimentary, Metamorphic

Varieties

 -   Mixture of blue Azurite and green Malachite.

Uses

When found in large pieces, the banded variety of Malachite makes a precious ornamental stone. Small ornamental objects, such as boxes and animal figures, are carved out of this compact stone, and if properly polished, they can be valuable. Malachite is also used as a minor gemstone, and is cut into cabochons and fashioned into necklace beads. "Azure-malachite" is also used as gemstone and has the same gem applications as banded Malachite. Malachite is very popular among mineral collectors, especially interestingly shaped and banded specimens. It is also used as an ore of copper and crushed to make a green pigment.

Noteworthy Localities

There are many places where fine Malachite comes from. Only the best will be mentioned here. Much of the original gem material, from which ornaments and jewelry were made since early times, was from the large deposits in Yekaterinburg Oblast in the Ural Mountains of Russia.

Africa contains several outstanding Malachite deposits. The mines at Katanga (Shaba), especially at Kolwezi, in the D.R. Congo (Zaire) produce Malachite in all sorts of odd shapes and forms, and are the source of the best banded, concentric, stalactitic and sparkling specimens. Tsumeb, Namibia, has also produced some of the best Malachite, especially Malachite pseudomorphs after Azurite. The Emke Mine in Ogonja, Namibia is also an outstanding Malachite locality. Morocco also contains fabulous Malachite sources, specifically in Touissit and Kerrouchene.

Australia contains important Malachite localities at Burra Burra, South Australia; the Rum Jungle, Batchelor, Northern Territory; and the Sir Dominick Mine, Flinders Ranges, South Australia. A new specimen producer is China, where gorgeous Malachite comes from the Shilu Mine, Yangchun, Guangdong Province, with amazing stalactites worthy of special mention. Chessy, in the Rhône-Alpes, France, is an old and classic locality, where excellent pseudomorphs of Malachite after Cuprite occur in octahedral and even dodecahedral crystals.

Malachite from Brazil is especially prolific in Seabra, Bahia; and popular Mexican Malachite deposits include El Cobre, Concepcion del Oro, Zacatecas; and the now popular Milpillas Mine, Cananea, in Sonora.

In the U.S., Arizona is by far the most prolific producer of Malachite, and the mines at Bisbee, Cochise Co., are well known among all collectors for their outstanding variety and quality of Malachite. Other important Arizona localities are Morenci, Greenlee Co.; Ajo, Pima Co.; Mammoth-Saint Anthony, Tiger, Pinal Co.; and the Globe-Miami District, Gila Co.

Common Mineral Associations

Azurite, Chrysocolla, Limonite, Chalcopyrite, Copper, Calcite, Quartz

Distingushing Similar Minerals

Brochantite - Doesn't effervesce in hydrochloric acid; otherwise very difficult to distinguish the two minerals.


Close

Copyright © 2024. Minerals.net

View on Full Site