Mimetite

Formula: Pb5(AsO4)3Cl

Species: Arsenates

Colour: Pale-yellow, yellowish-brown, orangish-yellow, orangish-red, red, green, white, colorless; colourless or faintly tinted in transmitted light.

Lustre: Sub-Adamantine, Resinous

Hardness: 3½ – 4

Specific Gravity: 7.24

Crystal System: Hexagonal

Member of: Apatite Group > Apatite Supergroup

Name: Named in 1835 by François Sulpice Beudant from the Greek μϊμητής for “imitator,” in allusion to its resemblance to pyromorphite.

Type Locality:Treue Freundschaft Mine, Johanngeorgenstadt, Erzgebirgskreis, Saxony – Germany

Polymorph of: Mimetite-2M, Mimetite-M

Isostructural with: Pyromorphite, Vanadinite

Apatite Group: Apatite Supergroup. Mimetite-Pyromorphite Series and Mimetite-Vanadinite Series. The arsenate analogue of Pyromorphite and Vanadinite. There is a complete series between mimetite, pyromorphite and vanadinite. A secondary mineral found in the oxidized zones of lead deposits. Usually found as small hexagonal prisms, often plain but may be modified, sprinkled on the matrix thinly to thickly. Its colour is quite variable, ranging from pale yellow to yellowish-brown to orange-yellow to orange-red, brownish, greenish, white and colorless.