The carat is the unit of weight of precious gemstones.
The term comes from the Arabic “chirat”, the carob seed. In the past it was believed that they have always the same weight – about 0.20 grams. 1 carat diamond weighs 0.20 grams.
Diamond’s color scale depends on the slightest variations in its white tone.
The classification commonly used was established by the GIA, Gemological Institute of America. Colors definitions instead were standardized by the International Diamond Council.
While a scale exists for white diamonds, it doesn’t for fancy color and to define them are used adjectives such as vivid yellow, deep orange, intense green, light blue, etc.
Clarity depends on the size and type of inclusions inside the diamond.
Inclusions and blemishes alter the transparency and / or brilliance of the gem. Diamonds with higher clarity grades are more valued, with the exceedingly rare “Flawless” graded diamond fetching the highest price.
The most frequent inclusions are represented by crystals, fractures, growth plans.
The most striking feature of a gem is its shape.
Over time the shapes have changed, thanks also to the knowledge of new technologies. At the beginning raw stones were used directly for religious and ornamental purposes. The faceted cut came after a long time. Diamonds acquire the maximum brilliance thanks to the modern round brilliant cut. This cut is designed to reflect light optimally. It is composed of 57 facets and proportions studied by Marcel Tolkowsky in 1919.