Back-scattered electron scanning electron microscopy image of a polished section of the garpenbergite (Grp) type specimen, with carlfrancisite (Cfc), jacobsite (Jcb), alleghanyite (Alh), dolomite (Dol) and kutnohorite (Kut). The arrow points to one area (white) containing a fine intergrowth of stibarsen and paradocrasite. Sample GEO-NRM #20200040. The image is published in an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ). — Photo: Dan Holtstam, Luca Bindi, Hans-Jürgen Förster, Andreas Karlsson and Kjell Gatedal · CC BY-SA 4.0
Garpenbergite
Garpenbergite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn₆AsSbO₁₀(OH)₂.
It crystallizes in the orthorhombic crystal system (space group Ibmm). It is a member of the Manganostibite structural group.
Key properties: Mohs hardness 5; specific gravity 4.47; Brown streak; Sub-adamantine to greasy luster.
IMA status: approved, named in 2021.
Found in fractured skarn matrix of granular jacobsite, alleghanyite, kutnohorite and dolomite developed in metamorphosed sedimentary and volcanic rocks.
It is found associated with Carlfrancisite, stibarsen, paradocrasite, filipstadite.
The name refers to the place of discovery, Garpenberg. In the Middle Ages, ‘garp’ was the colloquial word in Swedish for a German person.