Diamond grading is carried out under independent strict laboratory conditions by a fully qualified and vastly experienced gem trades laboratory grader. Never fall into the trap of thinking that an in-house jewelry store laboratory is the same thing or as good as an independent grading laboratory, it’s not!
There are various inspections undertaken on a diamond to:
a) Check it’s validity
b) Report on its characteristics and quality
The process is involved and very strict but by the end of it quality certified diamonds are the result.
鑽石等級 both protects the consumer and the retailer from fraud and helps determine the price of any particular diamond.
Diamond Grading: 4 C’s Overview
G.I.A. reports are by far the most common of the two and A.G.S. reports follow the same format anyway.
Color: G.I.A. grades color from D to Z (Z being intense yellow) with D being colorless even under 10x magnification. The equivalent A.G.S. scale rises by halves with D being 0 and E being 0.5 etc..
Clarity: G.I.A. grades clarity from F (flawless) to I3 (included 3). A.G.S. equivalent scale rises by 1 for every grade, therefore 0 = Flawless 10= included 3 / I3.
Cut: G.I.A. measures the dimensions, proportions, symmetry and polish. Symmetry and polish are given grades from excellent to poor but there is no overall grade for the “make” of the cut. A.G.S on the other hand give similar reports on dimensions, proportions, symmetry and polish.
Carat: Both G.I.A and A.G.S. measure a diamond’s weight using the carat weight scale.