Crystal chemistry of meteoritic kirschsteinite
Folco, Luigi; Mellini, Marcellο
European Journal of Mineralogy Volume 9 Number 5 (1997), p. 969 - 974
published: Sep 24, 1997
manuscript accepted: Apr 1, 1997
manuscript received: Jul 23, 1996
ArtNo. ESP147050905006, Price: 29.00 €
Abstract Individual kirschsteinite grains from the Vulcano Laziale iron meteorite are chemically homogeneous, with compositions close to Ca1.00Feo0.61Mn0.17Mg0.22Cr0.002Si1.00O4.00. The crystal structure of two different crystals (Fa19F0.11La50 and Fa35F014La51, respectively) are refined (orthorhombic unit cell parameters: a = 4.877 and 4.875, b = 11.166 and 11.164, c = 6.448 and 6.447 Å), yielding similar results. In particular, the geometry of the M2 and T coordination polyhedra does not change with respect to other calcium bearing olivines, whereas Ml is sensitive to the site population.