Andesite, Plagioclase, Hornblende Root Name Group, Magnetite
Headrace Tunnel, Saguling Dam, Bandung Regency, West Java Province, Indonesia
The porphyritic rock illustrated shows phenocrysts of plagioclase, minor quartz, hornblende (various interference colors), and magnetite (black opaque), in a microcrystalline groundmass consisting mainly of plagioclase. Transmitted plane polarized light digital image, with crossed polarizers, width of image 2 mm.
G. Grundmann collection and ...
© Günter Grundmann, Detmold.