tenorite

{{infobox mineral | name = Tenorite | category = Oxide mineral | boxwidth = | boxbgcolor = | image = Tenorite - USGS Mineral Specimens 1083.jpg | imagesize = 260 | alt = | caption = | formula = CuO | IMAsymbol = Tnr | molweight = | strunz = 4.AB.10 | dana = | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/c | unit cell = a = 4.6837(5) Å b = 3.4226(5) Å c = 5.1288(6) Å; β = 99.47°; Z = 4 | color = Steel-gray, iron-gray, black | colour = | habit = Lathlike crystals, curved, scaly, dendritic; commonly pulverulent, earthy, massive | twinning = Common on {011}, forming stellate groups; lamellar | cleavage = Poor to indistinct | fracture = Conchoidal to uneven | tenacity = Brittle; flexible and elastic in thin scales | mohs = 3.5–4 | luster = Metallic to earthy | streak = Black | diaphaneity = Opaque, thin flakes transparent | gravity = 6.5 | density = | polish = | opticalprop = Biaxial (+) | refractive = | birefringence = | pleochroism = Distinct; light to dark brown | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} Tenorite, sometimes also called Black Copper, is a copper oxide mineral with the chemical formula CuO. The chemical name is Copper(II) oxide or cupric oxide.

==Occurrence== thumb|left|Tenorite with azurite from Nischne Tagilsk, Urals, Russia Tenorite occurs in the weathered or oxidized zone associated with deeper primary copper sulfide orebodies. Tenorite commonly occurs with chrysocolla and the copper carbonates, azurite and malachite. The dull grey-black color of tenorite contrasts sharply with the often intergrown blue chrysocolla. Cuprite, native copper and Fe–Mn oxides also occur in this environment.