Pyromorphite – Stribro, CZ

Pyromorphite is a mineral belonging to the phosphate group, specifically lead phosphate with the chemical formula Pb₅(PO₄)₃Cl. Pyromorphite is often associated with the oxidation zones of lead deposits, where it is formed as a secondary mineral during weathering of primary lead ores. This mineral is not only interesting for its chemical composition, but also for its aesthetic appearance and collector's value.

Characteristics

Pyromorphite occurs in a wide range of colours, from bright yellow, green, brown to orange. The green and yellow varieties are the most common and most popular among collectors. They form characteristic needle-shaped or cylindrical crystals which can reach different sizes. Pyromorphite is sometimes found in grape-like or spherical aggregates. It has a glassy to resinous lustre, which contributes to its attractive appearance.

Origin and locality

Pyromorphite occurs mainly in oxidised lead deposits, where it is the result of the chemical transformation of lead ores. It is often found together with other minerals such as galena, cerussite or anglesite.

The main deposits of pyromorphite are in countries such as Germany, Spain, China, the USA (especially Idaho), and Australia. German localities, especially in the Harz area, are known for their high quality pyromorphite specimens.