Rock Identifier
Tumbled copper-bearing rock, likely chrysocolla-bearing basalt or copper ore (Chrysocolla (hydrated copper phyllosilicate, approximately Cu₂H₂Si₂O₅(OH)₄·nH₂O) in a dark volcanic host) — mineral
mineral

Tumbled copper-bearing rock, likely chrysocolla-bearing basalt or copper ore

Chrysocolla (hydrated copper phyllosilicate, approximately Cu₂H₂Si₂O₅(OH)₄·nH₂O) in a dark volcanic host

AI-generated identification · may be incorrect

Blue-green, black, and brown mottling with a dull to earthy luster; likely hardness 2–4 for chrysocolla and 5–6 for the host rock. Massive rather than visibly crystalline, with no obvious cleavage; exact identification requires testing or analysis.

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Physical properties

Blue-green, black, and brown mottling with a dull to earthy luster; likely hardness 2–4 for chrysocolla and 5–6 for the host rock. Massive rather than visibly crystalline, with no obvious cleavage; exact identification requires testing or analysis.

Formation & geological history

Likely formed in the oxidized zone of a copper deposit, where groundwater altered primary copper sulfides; the dark matrix may be basalt or another mafic rock. Geological age cannot be determined from the photograph.

Uses & applications

Collected as an ornamental stone or lapidary material; polished pieces may be used for cabochons, carvings, and display. It has little industrial value unless copper minerals are sufficiently concentrated for ore processing.

Geological facts

The turquoise-blue to green coloration is characteristic of hydrated copper minerals, but similar colors can occur in malachite, pseudomalachite, or chrysocolla-coated rocks.

Field identification & locations

Look for blue-green earthy patches, a dark dense matrix, and possible green streak; chrysocolla is softer than quartz and may scratch more easily. Common sources include Arizona, Nevada, Chile, Peru, Australia, and the Democratic Republic of Congo.