How do I identify Cornubite?

Cornubite can be identified by its hardness of 4 on the Mohs scale, Apple green color. Look for these key characteristics when examining specimens.

What color is Cornubite?

Cornubite typically appears in Apple green, Light to dark green. Color can vary depending on impurities and formation conditions.

How hard is Cornubite?

Cornubite has a hardness of 4 on the Mohs scale. This gives it moderate hardness.

Cornubite

A variety of Minerals

What is Cornubite?

Cornubite is a rare secondary copper arsenate mineral with formula: Cu5(AsO4)2(OH)4. It was first described for its discovery in 1958 in Wheal Carpenter, Gwinear, Cornwall, England, UK. The name is from Cornubia, the medieval Latin name for Cornwall. It is a dimorph of Cornwallite, and the arsenic analogue of pseudomalachite.

Cornubite Market Value Calculator

Estimate the market value of Cornubite using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.

Cornubite Localities Map

See where Cornubite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

Map preview

North ZoneCentral RidgeSouth Basin

Key Characteristics

Characteristics of Cornubite

Cleavage is distinct in two directions, both perpendicular to the enlarged faces of the tabular crystals, intersecting at about 70°. Cornubite is fairly soft, with hardness 4, the same as fluorite, and specific gravity 4.64, which is similar to another copper arsenate, clinoclase, at 4.38, but much denser than quartz, at 2.66.

Composition of Cornubite

The structure is made up of sheets of edge-shared Cu(O,OH)6 octahedra, with a copper atom Cu in the middle of the octahedron and either oxygen O or hydroxyl OH at each of the six vertices. These sheets are connected together by AsO4 groups with an arsenic As atom in the middle and O at each of the four vertices. In the AsO4 groups three of the O's are shared with octahedra in one octahedral sheet, and the fourth O is shared with an octahedron in the adjacent sheet. Hydrogen bonds also connect the sheets together.