One of the Museum’s most spectacular mineral specimens is a 1,000-pound stibnite with hundreds of sword-like, metallic blue-gray crystals sprouting from a rocky base. Stibnite (Sb2S3), a compound of the elements antimony and sulfur, occasionally forms nests of delicate, six-sided crystals, but examples this large and intricate are exceedingly rare.
The unique specimen on display at the Museum was spared from destruction by alert miners in the Wuning (Wuling) antimony mine in Jiangxi Province of southeastern China. Stibnite is most commonly pulverized and heated to extract the antimony and make flame retardants and engine bearings. “That it survived the mining process at all is a miracle,” said George Harlow, Curator in the Department of Earth and Planetary Sciences. “This is truly one of nature’s treasures.”
The Museum’s stibnite specimen is the largest on public display in the world. It was likely formed some 130 million years ago when water heated by volcanic activity dissolved antimony and sulfur from surrounding rocks and flowed between layers of limestone, leaving a dense band of stibnite and occasional pockets containing long, elegant crystals.