Erlianite, a new vanadium- and iron-bearing silicate mineral

Abstract

AbstractErlianite was found in the Harhada iron deposit along the Jining-Erlian railway, Inner Mongolia Autonomous Region, People's Republic of China. The occurrence formed at a high pressure and low temperature and the mineral occurs sparingly, mainly on fracture surfaces on which there is evidence of movement. It is associated with quartz, magnetite, siderite, albite, stilpnomelane, minnesotaite, deerite, etc.Erlianite is black with a brownish streak, silky lustre and occur as fibres, flakes, and lath-like aggregates. The grain size is 1–2 cm. It is not fluorescent. H = 3.7, D = 3.11. Cleavages on {001} and {100} are perfect; orthorhombic Pmmn or Pm21n with a = 23.20, b = 9.20, c = 13.18, Å and Z = 1. Strongest lines are 11.5(100)(200, 101), 3.05(50)(223,130), 2.89(60)(603,800,231,621), 2.61(60) (523,105,332,224), 2.52(50)(901,115,033,531), and 1.560(50) (12.0.5,14.2.0). Biaxial negative with α = 1.667, β = 1.674, γ = 1.679, 2V = 56–59°. Analysis gave SiO2 38.80, FeO 26.67, Fe2O3 21.26, V2O5 1.15, MgO 1.00, CaO 0.83, MnO 0.55, P2O5 0.051, K2O 0.079, Na2O 0.09, Al2O3 0.19, TiO2 0.38, H2O+ 7.65, H2O- 0.90, total 99.60%, leading to (Fe19.962+Fe2.193+Mg1.33Mn0.42)Σ23.90(Fe11.323+V0.68)Σ12(Si34.73Ti0.26Al0.20Fe0.813+)Σ36O90(OH,O)48 (one unit cell content for O = 138).The sample of the new mineral was discovered in 1977 during an investigation of an iron deposit which has been named ‘M14’. The methods used for studying this mineral included optical microscopy, X-ray powder diffraction, selected area electron diffraction analysis, wet chemical analysis, DTA, TGA, infra-red absorption and Mosbauer spectroscopy.