Rammelsbergite Locality: Ste Marie-aux-Mines (Markirch) , Haut-Rhin , Alsace , France ( Locality at mindat.org ) Size: 5.5 x 4.9 x 3.4 cm. An extremely rare old French rammelsbergite, from this classic mining district. The specimen is very rich with microcrystals, and a few larger aggregates to 5mm. Ex. Martin Zinn, Eric Asselborn, and F. John Barlow Collections. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Rammelsbergite
A silvery nickel diarsenide forming metallic orthorhombic prisms — hardness 5.5.
Intro adapted from Wikipedia (CC BY-SA).
Rammelsbergite is an IMA-recognized mineral species in the sulfide class, with the chemical formula NiAs₂.
It crystallizes in the orthorhombic crystal system (space group Pnnm). It is a member of the Löllingite structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 7.1; Grayish black streak; Metallic luster.
IMA symbol Rmb, grandfathered status — known before the IMA’s founding, named in 1845.
Found in hydrothermal veins formed at medium temperatures with other Ni–Co minerals.
It is found associated with Skutterudite, safflorite, löllingite, nickeline, bismuth, silver, algodonite, domeykite, uraninite.
The mineral was named to honor Karl Friedrich Rammelsberg (1813–1899), mineral chemist of Berlin, Germany. All rights reserved. No part of this publication may be reproduced.