What may happen to a rock/mineral is that the softer layers of a rock that are closest to the surface get weathered or eroded away while the harder center parts do not. This usually results in interesting and uneven rock shapes. Also, some weathering isn't exactly even in terms of the surface of a rock.
Are meatmorphic rocks and also perhaps soil.
All rocks can form from sedimentary because the rock cycle is endless.
igneous rocks form within earths surface
weathering of preexisting rocks form clastic sedimentary rocks, Oversaturated water basins form chemical sedimentary rocks after the water evaporates and dead sea organisms settle at the bottom forming biochemical sedimentary rocks.
Igneous Rock
Rounded smooth rocks typically originate from processes like erosion and river transport, where water gradually shapes them over time, resulting in their smooth appearance. In contrast, angular uneven rocks are often formed through geological processes such as volcanic activity or fracturing, which leave them with sharp edges and irregular shapes. The history of rounded rocks is often linked to their journey through water, while angular rocks often reflect their origins in solid geological formations. Both types of rocks tell unique stories about their formation and the environmental conditions they experienced.
Rounded smooth rocks typically indicate a history of significant erosion and transport, often through water, which has polished their surfaces over time. In contrast, angular uneven rocks suggest a more recent formation or limited transport, as they retain their sharp edges and corners. Analyzing these characteristics can provide insights into the geological processes at play, such as weathering, erosion, and the environments in which the rocks were formed or modified. Thus, studying their shapes and textures helps geologists infer their histories and the conditions of their surroundings.
a nonconformity
Angular sediments are sedimentary particles that have sharp or angular edges. They are typically derived from the erosion and fragmentation of pre-existing rocks and have not undergone significant rounding through transport. Angular sediments are often found close to their source and can provide clues about the geological processes that formed them.
Jagged-grained rocks are typically classified as igneous rocks, particularly those that form from the rapid cooling of magma or lava, resulting in a coarse, uneven texture. This texture is often associated with volcanic activity, where the rock cools quickly, leading to the formation of larger, angular crystals. Examples include basalt and andesite, which exhibit this characteristic jagged appearance. Additionally, some metamorphic rocks can also display a jagged grain due to their foliation or banding.
Rocks with a large grain size perhaps with angular grain shapes.
angular unconformity
A sedimentary rock called "breccia". The sharp angular pebbles making up the breccia could be igneous, sedimentary, or metamorphic. Breccias generally form close to the point of origin of the clast rock, having less time to round those sharp angular edges.
You can manually using water jet machine can engraving on uneven rocks.
spheroidal weathering
angular unconformity
Spheroidal weathering