stibnite
stib.nite \'stib-.ni-t\ n [alter. of obs. E stibine stibnite, fr. F, fr. L stibium antimony,]fr. Gk stibi, fr. Egypt stsub-dot>m : a mineral Sb2S3 consisting of antimony trisulfide occurring in orthorhombic lead-gray crystals of metallic luster and also massive