Rosasite is a secondary mineral found in the oxidation zone of copper-zinc deposits. Its color is an attractive blue, sky-blue, blue-green to green with a vitreous to silky luster. This colorful mineral is associated with numerous quality minerals, including Hemimorphite, Calcite, Smithsonite, Malachite, Quartz and Azurite.
The crystal system for Rosasite is monoclinic, typically found as crusts and botryoidal masses or nodules. Other forms include spherulitic, fibrous crystals in tufted aggregates, and radiating fibrous clusters.
Quality specimens are found in limited localities, including England, Italy (named after the Rosas mine), Mexico, Namibia and the USA (Arizona, Colorado, New Mexico and Utah).