The individual colors were classified and described very
early on. In the United States, then as now the country with the highest
portion of the diamond market, a system of diamond grading was first devised
at the beginning of this century with its own terms for color designation.
The various names of the colors, which originated from the then newly discovered sources in South Africa even today are still known as the "old terms" They have, to be sure, been replaced in the course of time in the USA and other countries by figure or letter systems, as well as by other descriptions.
The "old terms" were based on a colorless -> cape series with imperceptible transitions of nine color grades:
|Jager||Finest blue white|
|Top Wesselton||Fine white|
|Top Crystal||Finest Silver Cape|
|Top Cape||Fine Cape|
|Ught Yellow||Light Yellow|
Most of the old terms are derived from names of former diamond mines.
The term JAGER comes from the name of a South African diamond mine, the Jagerfontein Mine. This mine yields very many "finest blue white" diamonds. In the first attempts at a definition of the color; however, it was realized that the color stage Jager did not represent a slight blue suffusion, but that the visible bluish coloration present was caused by another phenomenon: by fluorescence.
It was observed in fact that some diamonds exhibit different colors in day and artificial light and it was deduced from that that the weak blue hue arose from. a concentration of ultra-violet rays in natural daylight (see chapter "Fluorescence", p. 40).
The term Jager as a description of the highest color grade was therefore struck out of the scale and River took over the first place:
For diamonds which were found in rivers or alluvial deposits the term. RIVER was adopted. Usually these stones were very transparent and of better color than diamonds found in pipes.
The Wesselton mine produced diamonds which were of overwhelmingly better quality than the slightly yellowish diamonds of the neighboring mines, so that WESSELTON became the description of colorless diamonds. Stones of the color stage TOP WESSEL TON, under suitable conditions, permit the experienced specialist to perceive a difference in the transparency, and in WESSELTON a "touch" of yellow suffusion. Under normal lighting conditions they have the appearance of colorlessness.
The term CRYSTAL must have been derived from crystal glass and indicates a very slight yellow tint. In the color stages TOP CRYSTAL and CRYSTAL even a less experienced specialist can - under a suitable light source discern a yellow tinge. For this reason in the first attempts at naming the colors the German equivalent for Top Crystal was "very, very slightly yellowish" and for Crystal very slightly yellowish".
But experience has shown that the description "yellowish" has a sales-inhibiting effect, so that these terms have been replaced in a new revision of the guidelines by better sounding descriptions, namely "slightly tinted white" and "tinted white". The inadmissible fancy descriptions, such as "commercial white" which are substituted from time to time in the diamond trade for designating Top Crystal and Crystal, likewise recognize that the term "yellowish" for the very faintly yellowish nuances are not exactly likely to promote sales.
The term CAPE originates, from the Cape of Good Hope, a coastal district in South Africa, As the diamonds coming from there were on average more intensely yellow than the Indian and Brazilian stones, diamonds with stronger yellow saturation were termed CAPE.
From Top Cape to Yellow the increasing yellow coloring is clearly perceptible even to the unpracticed eye, so that the descriptions "slightly yellowish" to "yellow" are justified.
Diamonds of the color grade YELLOW should not be imagined as being a completely saturated yellow, The color scale continues beyond the yellow stage through several imperceptible transitions to a completely saturated yellow, These color stages "beyond" yellow, however, already, belong to the fancy colors, as the occurrence of diamonds with increasingly saturated yellow coloration becomes rarer, and, with the natural rarity, their value rises once again, Descriptions such as "lemon yellow" and "CANARY" are applied to intensely yellow diamonds.
The "old terms" in the series, however, represent only
names without any definition of the colors, so that definable terms which
would at the same time incorporate a description of the colors were sought.
Preliminary definitions were included in the revision of the RAL 560 A 5 of 1963, with the following subdivision of the color-grades, in which the color designation JAGER was no longer included:
|Very, very slightly,
Very slightly yellowish
|Group with slight trace
yellowish of color
Light yellow/light brown
|color||Comparison table of different color grading systems|