Setting the record straight on Diamond grades

When diamonds became a commercial commodity, diamond grades had to be created due to the various parameters involved in diamonds specifically diamond color & clarity.

In 1953 Richard Liddicoat who was then the Chairman of the Gemological Institute of America unveiled the GIA’s D-Z system of color grading….with D being the “whitest” and Z being the “lowest color”.

“D” colored diamonds have a unique icy (read ice cube) look to them. High color diamonds is a term that is sometimes used to describe diamonds which tend to be between D-J while those below are termed as “Low color”.

The system which starts with the letter D was decided upon due to the commercial abuse of the then existing system which used terms like “river”, “top Wesselton” & “top silver cape”. Retailers began to lure & confuse customers with promises like extra, extra white stones.

Diamond grades that didn’t have any commercial appeal had to be developed. "D" which universally in academic circles signifies a low grade was decided upon as it couldn’t have consumer appeal.

These grades are available on a diamond grading chart.

See Below

After having a decade of experience in commercial diamond grading, the GIA improved their equipment & viewing environment in the 1960s; this was in order to obtain more consistent results.

The Clarity was also agreed upon within the industry and it has remained more or less constant.

See Chart below

The Argyle mine in Australia began to produce a lot of brown stones in the mid 1980s & so light-brown began to cover the full range of the scale. The GIA developed a set of brown master stones for use internally (master stones are Ideal cut diamonds that are used to compare other diamonds against). All brown diamond grades below “J” are noted with the letter grade & a color description.