大廠礦田

The Dachang ore field lies in Nandan County, in the mountainous north-west of Guangxi, China. It is one of the country's largest and most important tin-polymetallic districts — a major source of tin, zinc, antimony and lead — and ranks among the most significant non-ferrous metal districts in the world.

Geology and ores

Mineralisation at Dachang is hosted by Devonian carbonate and fine clastic rocks that were intruded and altered by granite at depth, producing a series of tin- and sulfide-rich orebodies. Cassiterite is the principal tin ore, and it occurs with an abundant sulfide assemblage — sphalerite, stibnite, arsenopyrite, pyrrhotite, pyrite, galena and a variety of sulfosalts — together with quartz and carbonate gangue.

For collectors

Beyond its economic output, Dachang yields collectable specimens: cassiterite crystals and twins, and well-formed sulfides such as stibnite, arsenopyrite and sphalerite, often in aesthetic associations on quartz. The district is a cornerstone of Chinese tin mineralogy and a name well known to collectors of Chinese sulfide minerals.