Why do rocks have a range of different appearances?

Answer 1

Some weathering processes simply fracture rocks, producing jagged fractures. Other weathering processes abrade or chemically dissolve the rock surface, producing smooth surfaces. Some rocks fracture along planes of weakness producing fairly smooth surfaces, like shale, or slate; other rocks fracture jaggedly, without orientation along planes of weakness, like granite.

Answer 2

Rocks that are smooth or rounded have been exposed to weathering, which could include tumbling in a river or stream, or abrasion from airborne rock particles, either of which will smooth rough surfaces.

Answer 3

The hardness, or tenacity, of a rock will be due to its mineral composition, their position in the rock cycle, and the design or composition of the fabric which holds the rock's grains together. Their texture is determined by formational factors, like time spent cooling from magma, depth of burial, and mineral composition.

Answer 4

bcoz they r in different environments. Environment is important for rock appearances.