international business - Rough Diamonds

Diamond is an allotropic form of carbon, the chemical formula C It is the thermodynamically stable form of carbon at pressures above 60 kbar. Marketed as precious gems, diamonds have a high added value. Typically, diamond crystallizes in cubic structure and can be industrially synthesized. Another form of crystallization of the hexagonal diamond is also known as lonsdaleita, less common in nature and lower hardness (7-8 on the Mohs scale). The feature that differs from other diamonds allotropic forms, is the fact that each carbon atom in sp ³ hybridized to be, and be connected to four other carbon atoms by covalent bonds in a tetrahedral three-dimensional arrangement. The diamond can be converted into graphite, the thermodynamically stable allotrope at low pressures, applying temperatures above 1500 ° C under vacuum or inert atmosphere. In ambient conditions, this conversion is extremely slow, becoming neglected. It crystallizes in the cubic system, usually in the form crystals with octahedral (8 sided) or hexaquisoctaédrica (48 faces), often with curved surfaces, rounded, colorless or colored. The dark-colored diamonds are little known and its value as a gemstone is smaller due to its unattractive. Unlike what was thought for years, diamonds are not forever as carbon decays over time, but diamonds last longer than any human being.
Being pure carbon, the diamond burns when exposed to a flame, turning into carbon dioxide. It is soluble in various acids and infusible, except at high pressures.
The diamond is the hardest naturally occurring material that is known, with a hardness of 10 (maximum value of the Mohs scale). This means it can not be scratched by any other mineral or substance, except the diamond itself, functioning as an important abrasive material. However, it is very fragile, this fact is due to the second perfect octahedral cleavage. These two features have made the diamond was not cut out for many years. The density is 3.48. The luster is adamantine, derived from the very high refractive index (2.42). Remember that all minerals with refractive index greater than or equal to 1.9 have this brightness. However, the crystals may have not cut a greasy shine. May fluoresce under ultraviolet light, resulting in colors blue, pink, yellow or green.