Penroseite is a rare selenide mineral with formula (Ni,Co,Cu)Se2. It has a gray-steel color and black streak with a hardness of 3. It is an isometric mineral, 2/m. Penroseite was first discovered in 1925 in a Bolivian rhyolite. It was named for Richard Penrose (1863–1931), an economic geologist.
{{Infobox mineral | name = Penroseite | category = Selenide minerals, pyrite group | boxwidth = | boxbgcolor = | image = Penroseite-217412.jpg | imagesize = | caption = Penroseite from Pakajake Canyon, Chayanta Province, Potosí Department, Bolivia | formula = (Ni,Co,Cu)Se2 | IMAsymbol = Pen | molweight = | strunz = 2.EB.05a | dana = 02.12.01.04 | system = isometric | class = Diploidal (m) H-M symbol: (2/m ) | symmetry = Pa | color = Steel gray | habit = Radial, columnar, reniform | cleavage = {001} Perfect, {011} Distinct | fracture = Subconchoidal | tenacity = Brittle | mohs = 2.5 - 3 | luster = Metallic | diaphaneity = Opaque | pleochroism = | streak = Black | gravity = 6.58-6.74 | references = }}
Penroseite is a rare selenide mineral with formula (Ni,Co,Cu)Se2. It has a gray-steel color and black streak with a hardness of 3. It is an isometric mineral, 2/m. Penroseite was first discovered in 1925 in a Bolivian rhyolite. It was named for Richard Penrose (1863–1931), an economic geologist.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).