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.
Examples of gemstones formed in igneous rocks include tourmaline, aquamarine, topaz, kunzite, and feldspars like sunstone and amazonite. Many other gemstones can be found within igneous rock formations but they are not a direct result of the formation of igneous rocks. They are called secondary deposits because they form after the primary deposit.