A mineral collectors dream: Crystal rain: A ball of platy crystals of plagioclase ejected as crystal lapillus from the 1975-1976 eruption of the Large Fissure of the Tolbachik volcano during an explosive eruption. The crystals are somewhat damaged from the fall. The crystals are covered by a thin crust of volcanic glass. The plagioclase are mixtures of anorthite-albite. The anorthite contence can be rather low. Bolshoe treshinnoe Tolbachinskoe izverkhenie, by S.A. Fedotov, 1984, page 242 states that the Lapilli consist of 20 to 80% of anorthite. Most of the feldspar of the lapilli are zoned. Specimen size: 2,3 cm. The specimen was provided by the Russian mineralogist Pavel M. Kartashov, and it is now in the collection of OT. Ljostad.
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