Diamond, the birthstone of April, is also the traditional tenth and sixtieth anniversary gift. The name diamond refers to its hardness (Greek - adamas: unconquerable, unbreakable). Diamonds have the highest scratch hardness (10) and thermal conductivity of any known material. It has an extremely rigid lattice structure that can only be contaminated by very few trace elements like boron causing blue or nitrogen causing yellow. Other colors (such as brown, red, pink, orange and purple) can be cause by patterns of interstitial vacancies (vacuoles) or lattice defects changing the light absorption and therefore the color. Green colors are cause by irradiation.
Colors can be changed in some types of diamonds by irradiation and/or heat either naturally or or color coating by man. Diamonds also can be lab coated in colorless or fancy colors by Chemical Vapor Deposition (CVD) or High Pressure/High Temperature (HPHT) methods.
Any time someone purchases a diamond or any gemstone, any treatments or special handling requires meats or whether its natural or created should be disclosed before it's sold.