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Gemstones 250x250

The Mineral adamite

Yellow Adamite on Limonite

Adamite occurs in many different lively colors. Different impurities are responsible for the color types. When copper is present in Adamite, this gives a vibrant green or blue color, and when cobalt is present, it gives a pink to purple color. Some impurities such as copper prevent the Adamite from its habit of being fluorescent.

Adamite crystals are usually embedded in rusting, crumbly, brown Limonite matrix that stain the hands. Since the Limonite crumbles when scrubbed, care must be exercised when washing such specimens.

Chemical Formula

Zn2(AsO4)(OH)

Color

Light to dark yellow, greenish yellow, green, greenish blue, sky blue, pink, purple, orange; rarely colorless, white, or red. Sometimes multicolored.

Crystal System

Orthorhombic

Properties

Streak
White
Hardness
3.5
Transparency
Transparent to translucent
Specific Gravity
4.3 - 4.5
Luster
Vitreous to adamantine
Cleavage
1,1 ; 3,1
Fracture
Uneven
Tenacity
Brittle
Other ID Marks
Fluorescent green or yellow-green in shortwave ultraviolet light.

Crystal Habits

As clusters of short, stubby crystals, but sometimes occurs in elongated prisms, usually in groupings. Also occurs acicular, radiating, and globular.

3D Crystal Atlas

Additional Information

Composition
Basic Zinc Arsenate. May contain appreciable amounts of copper and cobalt.
In Group
Phosphates; Arsenates
Striking Features
Association with Limonite and fluorescence.
Environment
As a secondary mineral in the oxidation zone of hydrothermal replacement deposits.
Rock Type
Sedimentary, Metamorphic

Other Names

Adamine

Varieties

 -   Adamite containing cobalt in its structure, which replaces some of the zinc. The presence of cobalt gives this variety a purple color. Its chemical formula is (Zn,Co)2(AsO4)(OH).
 -   Adamite containing copper in its structure, which replaces some of the zinc. The presence of copper gives it a vibrant blue to green color. Its chemical formula is (Zn,Cu)2(AsO4)(OH).

Uses

Adamite is a fine specimen mineral, and is in demand by mineral collectors for its pretty crystals. Adamite is a minor ore of zinc.

Noteworthy Localities

The most magnificent occurrence for this mineral is without doubt the Ojuela Mine in Mapimi, Durango, Mexico, where large, beautiful, and highly fluorescent examples occur in all different colors. Other important occurrences are Lavrion, Greece; Cap Garonne, France; Tsumeb, Namibia; the Brenner Mine, Dal'negorsk, Russia; and Nandan, Guangxi, China. In the U.S., the best occurence is Gold Hill, Tooele Co., Utah. Small colorless crystals were also found at Chloride Cliff in Death Valley, Inyo Co., California.

Distingushing Similar Minerals

Olivenite - Usually has a greener color and usually occurs in tall, thin crystals.
Smithsonite - Usually occurs globular, and doesn't fluoresce.
Paradamite - Different crystal form.


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