Original paper
A first natural occurrence of triclinic sincosite, Ca(VO)2(PO4)2∙4H2O, from the South Rasmussen Ridge Mine, Idaho, USA
Mumme, William G.; Grey, Ian E.; Gable, Robert W.; MacRae, Colin M.; Loomis, Tom
Neues Jahrbuch für Mineralogie - Abhandlungen Band 196 Heft 3 (2020), p. 261 - 268
16 references
published: Jul 24, 2020
published online: Jan 1, 2000
manuscript accepted: May 13, 2020
manuscript revision received: May 13, 2020
manuscript revision requested: Nov 14, 2019
manuscript received: Sep 26, 2019
ArtNo. ESP154019603006, Price: 29.00 €
Abstract
A single-crystal structure analysis of sincosite from the South Rasmussen Ridge mine, Idaho, USA has confirmed it as the first natural occurrence with triclinic symmetry. Previous work on the mineral, based on limited electron diffraction and single crystal studies, together with the indexing of powder X-ray diffraction data, have described it as having tetragonal symmetry; although hydrothermally prepared synthetic sincosite is triclinic. The unit cell parameters are a = 6.3531(12), b = 6.3567(14), c = 6.6050(18) Å, α = 106.995(22), β = 94.115(19), γ = 90.006(16)°, and the space group is P1. The crystal structure was refined to wRobs = 0.11 for 783 reflections with I > 4σ(I). The structure refinement and electron probe micro analysis both confirm the composition as Ca(VO)2(PO4)2∙4H2O.
Keywords
natural triclinic sincosite • crystal structure • composition • South Rasmussen Ridge Mine • Idaho • USA