Grading, historically speaking

The history of diamond colour grading can shed some light on how scales were developed and how they correspond to a stone’s price. In Europe, early colour grading terminology was based on well-known diamond-producing mines, with very little mention of hue.

For instance, the whitest diamonds were identified as ‘Jager.’ This term derives from the Jagerfontein mine in South Africa, which was known to produce the whitest diamonds with very strong blue fluorescence. At the same time, an equivalent scale existed in North America. Here, a ‘Jager’ was classified as ‘finest blue white.’ Similarly, the term ‘river’ was used when referring to diamonds that were found in alluvial or river deposits; these were considered to be, on average, whiter than stones found in mines (Figure 1).

The term ‘Wesselton’ referred to the mine of the same name, while ‘crystal’ was used to describe the light yellow tint that was evident in the glassware of the time. And finally ‘Cape’ was a reference to the mine located in the coastal town of Cape of Good Hope in South Africa. This mine produced a wide range of yellow diamonds, including the famous canary. The range of Cape diamonds was further divided by the intensity of colour.

Through this part of the colour scale’s development, the primary focus of the terms was to avoid the use of the word ‘yellow,’ since a stone described this way meant it was sub-par. However, in the case of diamonds that would be graded light yellow and lower, the intensity of the colour would characterize the stone as fancy.

The European and North American scales are two of many used historically in the diamond industry. In all cases, they range from white to yellow, with no mention of brown. Until the early 1980s, the total number of brown diamonds mined was insignificant. For the most part, they were considered worthless, and in many cases, labelled industrial-quality, with little to no use in the retail sector.