a zinc sulfide mineral that occurs typically in Potosí, Bolivia; Butte, Mont.; and Goldfield, Nev. It is a rare and unstable (at temperatures below 1,020° C, 【1,870° F】) hexagonally symmetrical modification of sphalerite, to which it inverts crystallographically; it may be made artificially from sphalerite by rapid cooling from 1,020° C. For detailed physical properties, see sulfide mineral (table).