Grain shape.
Pure obsidian actually has a glassy texture (grain), with no discernible crystalline structure.
texture
texture
tat is very large grain .. its not having a fine texture..
Sedimentary rock usually exhibits stratification, or layering of sediments.
Grain size and arrangement.
Tactile texture is the physical texture or actual texture on a surface that you can feel by touching. Tactile texture can include wood grain, fur, or sand as well as a smooth surface of glass or metal.
fined grain texture
Granite has a heterogeneous grain pattern or texture.
Fine grain, rough and soft
Grain
Grain
Grain
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.
Pure obsidian actually has a glassy texture (grain), with no discernible crystalline structure.
no
Yes simple as that.