Gruesome California Crime Stories That May Play A Part In âTrue Detectiveâ Season 2. Nic Pizzolatto isnât letting us into his warped, deviant mind when it comes to salient plot points surrounding the second season of the highly-acclaimed HBO anthology series, True Detective, but he has dropped a few hints.
Rhyolite: Fine-Grained Felsic Rock Most rhyolites are light gray to pinkish in color, but red or even black rhyolites are not rare. Most rhyolites are porphyritic and are identified by the quartz phenocrysts and white to salmon K-feldspar phenocrysts. The groundmass is aphanitic or even glassy.
In some cases gneisses are produced by higher grade metamorphism than schists. Low-grade metamorphic rocks tend to be fine-grained (the newly formed metamorphic mineral grains that is). High-grade metamorphic rocks tend to be coarse-grained. But grain size is also dependent on the grain size of the protolith.on-foliated metamorphic rocks include quartzite, which is metamorphosed sandstone in which the quartz grains have recrystallized into a very solid interlocking network, and marble, which is metamorphosed limestone composed of recrystallized and interlocking calcite or dolomite crystals.