1. Cleavage is a type of secondary foliation associated with fine grained rocks . 2. For coarser grained rocks , schistosity is used to describe secondary foliation. 3. Because of this quick cooling, the basalt is a fine-grained rock . 4. Shale is a fine-grained rock made of ancient silt and clay. 5. These are fine-grained rocks , not usually banded, nearly black in color with small red spots of garnet. 6. They are dark, fine-grained rocks , containing a few visible crystals of the minerals olivine, plagioclase, and quartz. 7. Coarse grained rocks are formed very slowly, while fine grained rocks are formed quickly, on geological time scales. 8. Coarse grained rocks are formed very slowly, while fine grained rocks are formed quickly, on geological time scales. 9. The formation holds natural gas in a fine-grained rock matrix which requires hydraulic fracturing to release the gas. 10. Conglomerates are coarse grained rocks dominantly composed of gravel sized particles that are typically held together by a finer grained matrix.
