Pyromorphite

Pyromorphite is a lead chlorophosphate mineral, Pb₅(PO₄)₃Cl, prized by collectors for its brilliant hexagonal crystals in shades of apple-green, honey-yellow, orange, and brown. It forms as a secondary mineral in the oxidised zones of lead-bearing veins, typically alongside galena, cerussite, mimetite, and vanadinite, of which it is isostructural.

Classic localities have shaped its reputation for over two centuries. The Bad Ems District in Germany is the type-defining locality, producing stubby brownish barrel-shaped crystals known as "Emser Barrels." The Les Farges Mine in Corrèze, France, is legendary for deep green, needle-like and barrel-shaped crystals on baryte matrix, while the Bunker Hill Mine in Idaho, USA, yielded honey-yellow to bright green crystal clusters that remain American classics. Other historic sources include Příbram in Czechia, Cordoba and El Horcajo in Spain, and the Caldbeck Fells in England.

In recent decades, the Daoping Mine and neighbouring Yangshuo Mine in Guangxi, China, have redefined the standard for the species, producing neon apple-green, gemlike crystals of extraordinary lustre that command premium prices among specialists. Broken Hill in Australia and the historic Kabwe Mine in Zambia have also produced fine fawn-to-purplish specimens. With such striking colour range, crystal habit variety, and a roster of world-famous type localities, pyromorphite remains one of the most sought-after secondary lead minerals for both thematic and aesthetic collections.