euhedral biotite mafic micas hornblende tremolite nepheline peridotites mica metamorphic rhyolite scapolite igneous gabbro calcareous Forsterite schist feldspars beryl cyanobacteria andalusite Chlorite labradorite serpentinite plagioclase Cumulate sphalerite clays sanidine garnets ultramafic augite xenoliths silicate basalt oun calcite enstatite green