A backscattered electron image (BSE) showing a rounded, subhedral grain of iridium enriched in Os (labeled Ir-Os) which hosts globular or elongate inclusions of PGE- and base-metal sulfides (gray in the BSE) from the River Ko placer. An intermediate member of the ferrotorryweiserite–torryweiserite series (labeled Ftyw) occurs as a portion of a composite and partial rim deposited around an olivine-plagioclase core (dark gray in the BSE), which includes skeletal forms of titaniferous augite. The host is epoxy. 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: {Barkov, Andrei Y. and Tolstykh, Nadezhda D. and Tamura, Nobumichi and Martin, Robert F. and McDonald, Andrew M. and Cabri, Louis J. · CC BY 4.0
Ferrotorryweiserite
Ferrotorryweiserite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Rh₅Fe₁₀S₁₆.
It crystallizes in the hexagonal crystal system (space group R-3m).
Key properties: specific gravity 5.93; Metallic luster.
IMA symbol Ftyw, IMA status: approved, named in 2022.
Found in fluvial placers likely derived from chromitites within ultramafic rocks of a layered complex of dunite-peridotite-gabbro.
It is found associated with Oberthürite or Rh-bearing pentlandite, laurite, a Pt-Pd-Fe alloy (likely isoferroplatinum and Fe-Pd-enriched platinum).
The prefix indicates the Fe-analogue of torryweiserite.