Folks usually surprise why the colour grading scale begins at D and not at A. The reply to that is really a quite simple one. At one time, the colour scale really did begin at A. Along with beginning at A, colour methods have been additionally assigned numbers (0, 1, 2,3), Roman Numerals (I, II, III) and even (AA). Classifications resembling “gem blue” “advantageous white” or “blue white” have been used as colour descriptions. These colour grading methods have been loosely utilized and usually instances, inaccurate and inconsistent. Early on, when the diamond commerce developed, diamond grades have been developed by varied events throughout the commerce. These unique scales by no means included the letter D and when the Gemological Institute of America (GIA) created the brand new scale in 1953, they determined to begin recent with a letter that was not part of the earlier grading system.
The GIA scale is now the official colour grading scale and has common acceptance amongst laboratories and trades-folks. This present scale ranges from D to Z, with D being colorless to Z which is a light-weight yellow or brown. The time period colour with reference to diamonds really refers to its lack of colour and the much less colour a diamond has, the rarer and extra precious it’s. Brown or yellow diamonds which have extra intense colour than Z on the grading scale are thought-about “fancy colours”. These diamonds are graded by a separate system fully and this identical system is often used for grading coloured gems like rubies, sapphires, and emeralds.