Herderite

Herderite with Albite Shigar Valley, Skardu District, Baltistan, Gilgit-Baltistan, Pakistan Size: 5.5 x 5.5 x 4.0 cm (miniature) © danweinrich
Chemical Formula: CaBePO4(F,OH)
Locality: Ehrenfriedersdorf, Saxony, Germay..
Name Origin: Named for Siegmund August Wolfgang von Herder (1776-1838), mining official in Freiberg, Saxony, Germany.Herderite is a phosphate mineral belonging to the apatite, phosphate group, with formula CaBePO4(F,OH) . It forms monoclinic crystals, often twinned and variable in colour from colourless through yellow to green. It forms a series with the more common hydroxylherderite, which has more hydroxyl ion than fluoride.It is found in many parts of the world, often in pegmatites and associated with other apatite minerals.It was first described in 1828 for an occurrence in the Sauberg Mine, Erzgebirge, Saxony, Germany. It was named for Saxon mining official Sigmund August Wolfgang von Herder (1776–1838).

Physical Properties

Cleavage: {110} Indistinct
Color: White, Yellowish white, Greenish white.
Density: 3
Diaphaneity: Transparent to Translucent
Fracture: Sub Conchoidal – Fractures developed in brittle materials characterized by semi-curving surfaces.
Hardness: 5 – Apatite
Luminescence: Non-fluorescent.
Luster: Vitreous (Glassy)
Streak: white

Photos :

Herderite Brazil Thumbnail, 9.5 x 5.5 mm ; 1.41 carats © irocks
Herderite Brazil Thumbnail, 7.6 x 5.9 mm ; 1.66 carats © irocks
Davib East Farm 61 (Davib Ost Farm), Karibib District, Erongo Region, Namibia © 2005 M. Kampf
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