Yarlongite occurs in ophiolitic chromitite at the Luobusha mine (29°5′N 92°5′E, about 200 km ESE of Lhasa), Qusum County, Shannan Prefecture, Tibet Autonomous Region, People's Republic of China. Associated minerals are: diamond, moissanite, wiistite, iridium ("osmiridium"), osmium ("iridosmine"), periclase, chromite, native iron, native nickel, native chromium, forsterite, Cr-rich diopside, intermetallic compounds Ni-Fe-Cr, Ni-Cr, Cr-C, etc. Yarlongite and its associated minerals were handpicked from a large heavy mineral sample of chromitite. The metallic carbides associated with yarlongite are cohenite, tongbaite, khamrabaevite and qusongite (IMA2007-034). Yarlongite occurs as irregular grains, with a size between 0.02 and 0.06 mm, steel-grey colour, H Mohs: 5^1/2-6. Tenacity: brittle. Cleavage: (0 0 1) perfect. Fracture: conchoidal. Chemical formula: (Cr4Fe4Ni)29C4, or (Cr,Fe,Ni)29C4, Crystal system: Hexagonal, Space Group: P63/mc, a = 18.839(2) A, c = 4.4960 (9) A, V = 745.7(2) A^3, Z = 6, Density (calc.) = 7.19 g/cm3 (with simplified formula). Yariongite has been approved as a new mineral by the CNMNC (IMA2007-035). Holotype material is deposited at the Geological Museum of China (No. Ml1650).
SHI NichengBAI WenjiLI GuowuXIONG MingFANG QingsongYANG JingsuiMA ZheshengRONG He
A new mineral species, named naquite(FeSi), is found in the podiform chromitites of the Luobusha ophiolite in Qusong County, Tibet, China. The detailed composition is Fe 65.65, Si 32.57 and Al 1.78 wt%. The mineral is cubic, space group P213. The irregular crystals range from 15 to 50 μm in diameter and form an intergrowth with luobusaite. Naquite is steel grey in color, opaque, with a metallic lustre and gives a grayish-black streak. The mineral is brittle, has a conchoidal fracture and no apparent cleavage. The estimated Mohs hardness is 6.5, and the calculated density is 6.128 g/cm3. Unit-cell parameters are a 4.486 (4) A, V 90.28 (6)A^3, Z=4. The five strongest powder diffraction lines [d inA(hkl) (I/I0)] are: 3.1742 (110) (40), 2.5917(111) (43), 2.0076 (210) (100), 1.8307 (211) (65), and 1.1990 (321) (36). Originally called 'fersilicite', the species and new name have now been approved by the CNMNC (IMA 2010-010).
SHI NlchengBAI WenjiLI GuowuXIONG MingYANG JingsuMA ZheshengRONG He