CONICHALCITE WITH GREEN CALCITE, MINERALES MEXICANOS MINE SANTA EULALIA CHIHUAHUA MEXICO (small cabinet)

Conichalcite is a green arsenate mineral made up of basic copper calcium arsenate, typically located in the oxidation zone of copper deposits. It is a relatively rare yet widespread mineral, found in regions such as Spain, England, the United States, Mexico, Chile, and Namibia. Conichalcite is classified as a secondary mineral, which means it originates from the alteration of other minerals, often enargite, within oxidized copper deposits.

Here's a more detailed overview of conichalcite:

Formation and Composition:
Chemical Formula: CaCu(AsO4)(OH) 
Formation: Conichalcite develops as a secondary mineral in the oxidation zone of copper deposits, generally resulting from the alteration of other minerals, such as enargite.
Appearance: It typically manifests as green, botryoidal (cluster-of-grapes) formations or crusts, and can also present in a powdery form.

Key Characteristics:
Color: Green, yellow-green, or greenish yellow, occasionally exhibiting a light green to yellowish green hue when viewed in transmitted light.
Luster: Sub-vitreous, greasy, or earthy.
Hardness: 4.5 on the Mohs scale.
Specific Gravity: Approximately 4.33.