THE STUDY OF MICRODIAMONDS AS AN INDEX MINERAL IN PETROLOGY OF IGNEOUS AND METAMORPHIC ROCKS

Diamond is a type of mineral that has an obvious formation condition with specific pressure-temperature range. This range leads to formation and crystallization of diamond in various sizes, types, and colors. Thus, this variety and physical as well as chemical properties of each crystal reflect the dominant conditions on the formation’s environment. Similar to large-crystal diamond, micro-diamonds reflect the conditions of pressure, temperature and chemical interactions within the environment of their formation. That is why this type of mineral has been distinguished in high-grade metamorphic rocks and igneous rocks. Appearance of various colors on micro-diamond has been the characteristic of chemical exchanges and indicates the arrival of elements such as nitrogen, Boron, titanium and other rare and trace elements to the crystal structure. In addition, considering the shape and habit of micro-diamond crystalline, and especially evaluation of the effect of the compression and tensile procedures on their crystallization system, one can achieve an overview of the dominant conditions on the metamorphic formation environment. Furthermore, the emergence and crystallization of this mineral both in metamorphic and igneous rocks can be considered as an indicator of similarity between the formation conditions in these two environments.