Optical identification of the alteration Products of olivine and pyroxene

Abstract

Saponite, bowlingite, nontronite, vermiculite, celadonite, chlorite, serpentine, bastite, cummingtonite, hastingsite, uralite, chlorophaeite, and iddingsite have all been cited in the literature as alteration products of olivine or pyroxene. Their optical properties, form, chemical composition, and nomenclature have been summarized here. Petrographic investigation of thin sections of five olivine- and/or pyroxene-bearing rocks in the U.N.B. Dept. of Geology collections in addition to thin sections of two cores from an altered ultramafic body at Island Lake, Manitoba resulted in the identification of the following alteration products of olivine, clinopyroxene, or hypersthene: iddingsite, chlorophaeite, saponite, nontronite, chlorite, clinoamphibole (hastinsite or uralite).