Being ruby the birthstone of July, let’s revisit a clarification on the term “pigeon’s blood”:
Ruby, a gem variety of the mineral corundum, is, by definition of its varietal name, red. There are however different reds, depending on the tone (how dark or light), saturation (the “quantity” of colour sort of saying) and the presence of absence of secondary colour (e.g. purplish).
In Mogok, Myanmar, where most gem rubies have been historically found, the “pigeon’s blood” colour descriptor, “kho thwe” in Burmese, was used for the pure red of the finest local rubies, particularly those that did not have the typical pinkish of this occurrence.
First recorded in English in late-1830s, the term was not used by most laboratories until recently and it can be seen in reports despite the lack of standardization in its definition, let alone the lack of agreement in its use itself.
Despite the fact that it is not a universally consensual trade term (many stake holders have different conceptions of what it means), it has been used in modern times based on certain criteria, e.g. red with no overtones, saturation and intensity, fluorescence and brilliance, all according to strict observation protocols (e.g. comparison with a master set).
The use of this colour descriptor, therefore, debatable in the trade as it lacks in consistency, harmonisation and standardisation for it is a commercial expression and not a gemmological term, and some even consider that it may be prejudicial to consumer confidence although it is recognised that it helps romancing the stone and in story telling that is so relevant and enourmously helpful in our industry. But at least let’s get the story right!
In the photo, the amazing Ratnaraj Ruby, a 10.05 ct ruby from Mogok, Myanmar, in a ring by Faidee, displaying the red over red effect that is characteristic for Pigeon’s Blood colour descriptor.
Guest articles by Rui Galopim de Carvalho:
https://gem-spectrum.com/category/rui-galopim-de-carvalho
About the author:
Rui Galopim de Carvalho is a renowned independent Gem Education Consultant, author, luxury industry training expert and popular international lecturer on gemmology and on the history of gem materials. During his 30 year experience as a gemmologist, Rui has studied important collections in both public and private museums, notably the Portuguese Crown Jewels.
Founder of the popular Home Gemmology webinar series launched during the COVID-19 lockdown, Rui has a long history as a gemmology communicator, notably on social media where he is a popular figure.
He is associate editor of Gem-A’s Journal of Gemmology, Vice-President of the Coral Commission of The World Jewellery Confederation – CIBJO, member of the Communications Committee of ICA (International Colored Gemstone Association), ambassador for LAUREL -Portuguese Association of Excellence Brands (ECCIA member) and consultant for several private collections and trade organizations.
Rui Galopim de Carvalho can be reached through his website:
