Rocks And Minerals


When they occur, crystals are acicular or prismatic, and ofter twinned. More usual habits are stalactitic, botryoidal masses with a fibrous, banded structure, and crusts. Malachite is a rich green and has a pale green streak. It is translucent to opaque, and it has a vitreous to adamantine luster on crystal face; fibrous habits have a silky luster.

*Formation: Forms in the oxidized regions of copper deposits, often with secondary minerals, including lazurite.

*Tests: It is soluble in dilute hydrochloric acid, with effervescence.

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