jinis
rocks pumice, rocks obsidian, rocks perlite, rocks porphyritic.
Flint, jasper, radiolarite, chert umum, chalcedony, agate, onyx, opal, magadi-jinis chert, porcelanite, Sinter siliceous
fitur
ngandhut asam ing alam, kasedhiya ing persil saka werna
clasts Gamelan kanggo tutul, gampang pecah dadi lancip piring, tahan struktural dhuwur marang erosi lan iklim