SSEF and Gübelin Gem Lab Agree on Color Standards

The two Swiss gem labs have agreed to harmonize their standards for the terms ‘pigeon blood red’ and ‘royal blue’

Swiss Gemmological Institute (SSEF) and Gübelin Gem Lab have announced that they have harmonized their standards for the terms pigeon blood red and royal blue in reference to rubies and sapphires.

Pigeon blood red rubies and royal blue sapphires have long referred to the finest examples of the respective stones, but there is not a definitive agreement on the criteria to denote the use of the phrase.

The two Swiss labs want to change that.

The labs had each independently developed their own criteria for the terms. They came together to compare criteria, and finding them very similar, set to define one standard for the terms.

The new standards for pigeon blood red rubies and royal blue sapphires are based on color and quality. To qualify for the term, the color must be “intense, saturated, and homogenous,” and the stones must not have undergone any modification of color or clarity. The standards are available in full at

“By applying these harmonized standards, it is the aim of SSEF and Gübelin Gem Lab to provide the trade with unified and consistent guidelines for the use of these historically significant terms,” said Michael Krzemnicki, director of SSEF.

“Clearly, such stringent sets of criteria implies that only a very small percentage of rubies and sapphires qualify,” said Daniel Nyfeler, managing director of the Gübelin Gem Lab. “This is in line with the experience and belief of both Gübelin and SSEF that historically only exceptional rubies and sapphires were attributed these quality terms.”

(Image courtesy SSEF and Gübelin)


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