【Switzerland】SSEF and Gubelin Gem Lab Harmonise Standards for ‘Pigeon Blood Red’ and ‘Royal Blue’ Gems

by

Editor’s Note

Two leading Swiss gemological laboratories have established unified standards for the trade terms “pigeon blood red” and “royal blue,” bringing long-awaited clarity to the high-end colored stone market.

None
Harmonization of Color Standards

Two reputed Swiss-based labs, widely regarded as being among the leading laboratories for coloured stone testing, have harmonised their standards for use of the terms “pigeon blood red” and “royal blue” to describe a gemstone’s colour.

These terms were traditionally used to describe only the finest quality rubies and sapphires respectively. However, till now, there was no definite agreement as to the precise colours and quality criteria that correspond to the two terms. This resulted in some confusion when these terms were used by different labs.

Both SSEF and Gubelin had been following their own strict criteria about which rubies and sapphires qualify for these colour terms, and after sharing this information between themselves, realised that they were more or less the same. Hence, they decided to harmonise standards.

Joint Standard Criteria

The joint standard that the labs will follow are:

1) Colour criteria:
Colour has to be an intense, saturated and homogeneous red or blue. “Pigeon blood red” is best described as a red colour, with no apparent colour modifiers (such as blue or brown). A minute purplish tint is acceptable. The body colour of pigeon blood red rubies is complemented by a strong fluorescence when exposed to ultraviolet light.

“Royal blue” is best described as a saturated blue colour, either pure or with a very slight purplish tint.

2) Quality criteria:
In terms of quality, these colour terms can only be applied to rubies and sapphires that exhibit fine qualities, and have not undergone any modification of colour and/or clarity, nor been subjected to any treatment. Furthermore, they must be relatively free of eye-visible or dark inclusions, and they must show a homogeneous colour distribution with vivid internal reflections.

Aim and Industry Impact

With this harmonisation, the two labs intend to foster a responsible and meaningful application of these terms in the trade.

“By applying these harmonised 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 Dr. Michael Krzemnicki, Director of SSEF.
“Clearly, such stringent sets of criteria imply that only a very small percentage of rubies and sapphires qualify,” stated Dr. 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.”
Full article: View original |
⏰ Published on: November 05, 2015