Rocks are commonly divided into three major classes according to the processes that resulted in their formation.
These classes are (1) igneous rocks, which have solidified from molten material called magma; (2) sedimentary rocks, those consisting of fragments derived from preexisting rocks or of materials precipitated from solutions; and (3) metamorphic rocks, which have been derived from either igneous or sedimentary rocks under conditions that caused changes in mineralogical composition, texture, and internal structure.
Geologic materials—mineral crystals and their host rock types—are cycled through various forms.
The process depends on temperature, pressure, time, and changes in environmental conditions in the Earth’s crust and at its surface.
Rock, in geology, naturally occurring and coherent aggregate of one or more minerals.
Such aggregates constitute the basic unit of which the solid Earth is comprised and typically form recognizable and mappable volumes.
The rock cycle illustrated in Diagenesis is, as previously explained, the process of forming sedimentary rock by compaction and natural cementation of grains, or crystallization from water or solutions, or recrystallization.
The conversion of sediment to rock is termed Rocks have many different textures.Poorly sorted sediment displays a wide range of grain sizes and hence has decreased porosity.Well-sorted indicates a grain size distribution that is fairly uniform.The volumetric portion of bulk rock that is not occupied by grains, crystals, or natural cementing material is termed porosity.That is to say, porosity is the ratio of void volume to the bulk volume (grains plus void space).She said she was 'shocked' by the creepy crawly and had 'never seen anything like it before'.