The first color is actually described as the adjective while the latter is in the noun form. For example, the modifying color of an orangy yellow diamond ring is orangy whereas the primary color is yellow.
The diamond ring in the above-mentioned example will be primarily yellow in color with a subtle orangy tint. In some cases, the color of fancy color diamond rings may be split in equal percentages. If that is the case, then the color of the diamond ring will be listed as two separate nouns like Orange Yellow.
Fancy color diamond rings that come with pure colors are extremely rare. As a result, they are a bit more valuable than other fancy diamond rings. The GIA (Gemological Institute of America) recently stated that there are just four fancy red colored diamonds in the earth, which means that the price of fancy red color diamond engagement rings will be a bit higher.