Semseyite is a rarely occurring sulfosalt mineral and is part of the class of lead antimony sulfides. It crystallizes in the monoclinic system with the chemical composition Pb9Sb8S21. The mineral forms dark gray to black aggregates.
via Wikipedia infobox
{{Infobox mineral | name = Semseyite | category =Sulfosalt mineral | image = Semseyite2.jpg | imagesize = 260px | caption = Semseyite - Brioude-Massiac (Massif Central) France (11x3.5cm) | formula = Pb9 Sb 8 S21 | IMAsymbol = Ssy | strunz = 2.HC.10d | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/c | unit cell = a = 13.64 Å, b = 11.96 Å c = 24.46 Å; β = 105.87°; Z = 4 | color = Dark gray to black | habit = Tabular, elongated prismatic crystals, commonly twisted; rosettelike groups | cleavage = Perfect on {112} | tenacity = Brittle | mohs = 2.5 | twinning = | luster = Metallic | diaphaneity = opaque | gravity = 6.15 | other = | references = }}
Semseyite is a rarely occurring sulfosalt mineral and is part of the class of lead antimony sulfides. It crystallizes in the monoclinic system with the chemical composition Pb9Sb8S21. The mineral forms dark gray to black aggregates.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).