clay
When it is broken down into an individual mineral grain or crystal, in which case it is a mineral.
Actually, obsidian doesn't have grains at all. Technically obsidian is a glass, which means it has no internal structure. When geologists refer the the grain size of a rock, they mean how big the crystals that make it up are. Since obsidian has no crystals, it therefore has no grain size.
Small to medium grain size.
It doesn't. The grain size effects the texture. If a rock has a small grain size, it will have a smooth texture. If the grain size is large, such as pebbles, the texture will be rough. For example, siltstone is one of the smoothest rocks because it contains silt particles, which are .0004cm to .006cm. Conglomerate though contains various particles including cobbles and boulders, which are from 10cm to 100cm.
Rocks don't come in particular sizes. Shale is a type of rock - it can be as small as a grain of sand or as large as a mountain range
Shale is a sedimentary rock that typically has the smallest grain size due to its fine-grained and compacted nature.
It varies some metamorphic rocks are fine grained (eg slate) and others have very large crystals (eg an augen gneiss).
Grain refers to particle or crystal size in rock.
yes, it does. when a grain size in an igneous rock is small, it means that it was probably an extrusive rock, meaning it formed on land. but if the grain size is big, it means that the rock most likely formed underground, or it was intrusive. try remembering it like this- the larger the crystals, the more time the rock had to form, and magma cools faster on land, not giving the rocks much time to form.
1.Grain Size 2.Grain Shape 3.Grain Pattern
The size of the grains in a sedimentary rock can be determined by examining the texture of the rock. Coarser grains indicate a larger grain size, while finer grains indicate a smaller grain size. Other features that can provide clues to grain size include the sorting (uniformity of grain sizes) and rounding of the grains.
Grain shape.