Quartz

Unknown Owner

Help improve this recordNo owner is registered for this specimen yet. If it's yours or you know more about it, you can add the owner, provenance, publications and other details.

A loose cluster of botryoidal purple crystallized quartz. In good condition with minimal micro-damage present.The Mamuju district, located in the West Sulawesi province of Indonesia, is the exclusive source of the distinctive botryoidal purple quartz popularly marketed as "grape agate." Geologically, this material is not a true agate but rather a form of chalcedony or amethystine quartz that formed within the cavities of volcanic host rocks, specifically andesite and rhyolite lavas. The unique spherical, grape-like clusters were created through a process of multi-directional crystal growth in gas bubbles or fractures within the cooling volcanic flows, often exhibiting colors ranging from pale lilac to deep royal purple. Historically, while the volcanic formations of Sulawesi have been known for decades, the commercial extraction of this specific quartz variety began in earnest around 2015 and 2016. The mining is primarily an artisanal, small-scale quarrying effort where local miners use hand tools to carefully extract the fragile clusters from the weathered volcanic matrix. Since its debut on the international market, Mamuju has remained the global epicenter for this material, with production continuing to support the high demand from the mineral collecting and lapidary communities.