Azurite

Azurite comes in several varieties of appearance: elongated or tabular prismatic crystals, often with striated faces, intergrown or in aggregates with a radiating structure. It is also common in stalactitic and globular aggregates. Translucent and rarely transparent, it is rather heavy, brittle and semi-hard, characteristics that make it easy to scratch. It is soluble with effervescence in dilute hydrochloric acid, is easily altered and, over time, becomes malachite.

This mineral forms in the oxidation zones of copper deposits, in a carbonate environment, often in aggregation with malachite, or with other copper minerals.

Used above all as an ornamental stone. In the past it was ground to obtain a colouring pigment much prized in painting.