Ravatite, C14H10, a new organic mineral species from Ravat, Tadzhikistan
Nasdala, Lutz; Pekov, Igor V.
European Journal of Mineralogy Volume 5 Number 4 (1993), p. 699 - 706
published: Jul 22, 1993
manuscript accepted: Feb 9, 1993
manuscript received: Oct 8, 1992
ArtNo. ESP147050504003, Price: 29.00 €
Abstract The new organic mineral ravatite (analyzed as C14.1H9.9, idealized formula C14H10), identical with synthetic phenanthrene, is described as a sublimation product caused by the natural combustion of a brown coal seam near Ravat/Tadzhikistan (southwestern Tjan' Shan'). It forms thin, platelet-like individuals with diameters of mainly a few hundred micrometers which are usually aggregated to thin crusts on a bituminous, H2SO4- impregnated coaly-earthy material. Ravatite is colourless, or - dependent on the amount of coaly, gas and other inclusions - white to pale grey and transparent to translucent. It shows a vitreous to wax-like lustre. Ravatite has a monoclinic lattice (space group P21) with a0 = 8.392(5)Å; b0 = 6.181(3)Å; c0 = 9.558(5)Å; ß = 98.48(12)°; V = 490.4(4)Å3; Z = 2. The observed strongest five X-ray powder diffraction lines [d in Å (lrei) (hkl)] are: 9.434(100)(001); 4.028(13)(201̄); 4.941(11)(110); 4.724(11)(002); 3.371(10)(211̄). The Mohs hardness is about 1; the calculated and the measured densities are 1.207(1) and 1.11 (2) g/cm3, respectively. Ravatite shows a whitish-yellow fluorescence under ultraviolet light. The initial temperature of melting is 94.3°C. Infrared absorption and Raman data do not differ significantly from data of synthetic phenanthrene.