TRANSVERSE CONTRACTION JOINTS. The primary purpose of transverse contraction joints is to control the cracking that results from the tensile and bending stresses in concrete slabs caused by the cement hydration process, traffic loadings, and the environment.
Diamonds are found in igneous rock which is brought to the surface of the earth by volcanic eruptions bringing magma to the surface. Diamond itself is strictly an allotrope of the element carbon, a mineral, one form of crystal that can be created from carbon.
Phaneritic rock has visible identifiable crystal grains. Aphanitic rock has crystal grains that are too small to be visible with the naked eye. In igneous rock, the difference is due to the amount of time spent in cooling. Long term cooling of magma underground leads to large crystals, rapid cooling of lava above ground leads to small crystal texture.