mimetite

{{Infobox mineral | boxbgcolor=#9c7a36| name = Mimetite | boxtextcolor = #fff | category = Arsenate minerals Apatite group | boxwidth = | image = Mimetite - Congreso-León mines, San Pedro Corralitos, Chihuahua, Mexico.jpg | imagesize = 275px | caption = Golden-yellow botryoidal mimetite from Congreso-León mines, Mexico | formula = Pb5(AsO4)3Cl | IMAsymbol = Mim | strunz = 8.BN.05 | system = Hexagonal | class = Dipyramidal (6/m) (same H-M symbol) | symmetry = P63/m | unit cell = a = 10.250(2) Å, c = 7.454(1) Å; Z = 2 | color = Pale to bright yellow, yellowish brown, yellow-orange, white, may be colorless | habit = Prismatic to acicular crystals; reniform, botryoidal, globular, | twinning = Rare on {112} | cleavage = [101] Imperfect | fracture = Brittle, conchoidal | tenacity = Brittle | mohs = 3.5–4 | luster = Resinous, subadamantine | refractive = nω = 2.147 nε = 2.128 | opticalprop = Uniaxial (−), anomalously biaxial | birefringence = 0.019 | pleochroism = Weak | streak = White | gravity = 7.1–7.24 | diaphaneity = Transparent to translucent | references = }}

Mimetite is a lead arsenate chloride mineral () which forms as a secondary mineral in lead deposits, usually by the oxidation of galena and arsenopyrite. The name derives from the Greek mimetes, meaning "imitator" and refers to mimetite's resemblance to the mineral pyromorphite. This resemblance is not coincidental, as mimetite forms a mineral series with pyromorphite () and with vanadinite (). Notable occurrences are Mapimi, Durango, Mexico, and Tsumeb, Namibia.