Gemmological Commission focuses on update of commercial colour-terms guidance document

ABOVE: Gemmological Commission President  Hanco Zwaan chairing the body’s session at the CIBJO Congress in Bahrain on November 19, 2019.

NOVEMBER 20, 2019

Colour-terms used by the commercial bodies to define certain coloured gemstones have long been an issue of contention in gemmological circles, where specialists are concerned that few if any universal standards have been created to protect consumers.

Gemmological Commission President Hanco Zwaan opened the body’s session at the 2019 CIBJO Congress on November 19 with a report on a commercial colour-terms guidance document which the Commission launched last year. It aims to map colour terms used to describe certain colours of ruby and sapphire.

On the issue of definitions of gem varieties, Mr Zwaan said that it is a clear that a definition does not exist. “It is a vast and complicated issue, but we agreed to look into it and set some minimum definition and then work from the easiest distinctions to the most difficult.”

Information has been added over the past year and the commercial colour-terms guidance document now reflects the positions of a number of important labs. It includes an attempt to show where the respective colours approximately lie referring to the Munsell colour charts.

Mr Zwaan told the meeting that the report provides information on commercial colours and terms, such as Pigeons Blood red, which are used by different labs. There are no international standards on the terms, but it is hoped there can be harmonisation regarding the terms, he stated.

“We tried to make an informative document and listed info from the SSEF and Gübelin labs,” he commented, adding that it also provides the positions on the issues of the GIA, Thailand’s GIT and the GRS, and a summary comparing the different labs’ positions.

“It is our intention to include the positions of more laboratories,” he added

Guillermo Galvis, President of ACODES in Colombia, reported on emerald harmonisation seminar that he attended in Hong Kong which dealt with emerald standards and future trends. He said that he took part in a dialogue with stakeholders in June and with lab representatives in September.

Mr Zwaan said: “Such dialogue is important and we must keep doing it. We need to look for comprehensive ways of raising standards to make it easier for consumers.”

Moving on, Mr Zwaan said there were no major amendments to the Blue Book, and they will only be implemented in 2021.

By |2019-11-20T10:58:48+00:00November 20th, 2019|NEWS|Comments Off on Gemmological Commission focuses on update of commercial colour-terms guidance document
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