Effenbergerite Locality: Wessels Mine (Wessel's Mine), Hotazel, Kalahari manganese fields, Northern Cape Province , South Africa ( Locality at mindat.org ) Size: 2.2 x 1.8 x 1.2 cm. Any Effenbergerite is a good Effenbergerite, considering how rare this species is, and how few specimens ever come to market. This is small, but it has several spots of eye-visible Effenbergerite crystallization upon it and should be considered significant enough to add to any rarities suite. TYPE LOCALITY. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Effenbergerite
The natural counterpart of Han blue pigment — a barium-copper silicate found in South Africa's Wessels mine.
Intro adapted from Wikipedia (CC BY-SA).
Effenbergerite is an IMA-recognized mineral species in the silicate class, with the chemical formula BaCuSi₄O₁₀.
It crystallizes in the tetragonal crystal system (space group P4/ncc). It is a member of the Gillespite structural group.
IMA symbol Efb, IMA status: approved, named in 1993.