Are rocks made of grains?
some rocks are, but those are a specific kind of rock. (a sedimentary rock is made of grains and or sediment, others are from hardened lava and pressure underground)
Detrital rocks are a kind of rock made from grains from minerals or other rocks that have been moved and deposited in layers?
Most simply, rocks are classified by how they are formed: igneous rocks are made by the setting of molten magma or lava sedimentary rocks are made when grains weathered from existing rocks settle to the bottom of water bodies, then get buried and compressed into rocks metamorphic rocks are made by the effects of heat and pressure on existing rocks, which cause them to recrystallise without melting.
Grains: Grains that are not crystals in rock do not have flat shiny faces. They are rounded, like grain of sand, or jagged, like a piece of broken rock. Grain Size: Grain size in rocks can mean the size of crystal grains or of fragments: Coarse Grained: most of the rock is made of grains as largeas rice, or larger.
Sedimentary rocks can be made from any kind of material, from other rocks to shells to fossils. Basically, any rock, from metamorphic to igneous and even to sedimentary, can be weathered and eroded. These particles and grains can be carried great distances by wind, water, ants, etc. before they are lithified (cemented) back together to form sedimentary rocks.