Spinel Buying and the Four Cs
Although red and blue colored spinels command the highest prices, clarity and carat weight can also have a significant effect on value. Myanmar (“Burmese”) provenance always adds value.
In the GIA color grading system, color consists of three qualities: hue, tone, and saturation. The basic hues are red, orange, yellow, green, blue, violet, and purple. Tone refers to a color’s relative lightness, from colorless (0) to black (10). Saturation refers to a color’s intensity, from grayish or brownish (1) to vivid (6). The dominant hue is capitalized. Other hues present are not capitalized and may be further described as “sl” for slightly and “st” for strongly.
Be aware when spinel buying that saturation or “spectral purity” is the color quality that will have the greatest impact on price. You could easily expect to pay five, ten or even twenty times as much per carat for the true red stone below on the right as for the less saturated pink one on the left.
Top color for so-called “ruby spinels” consists of…