Roskin Gem News Report

Pink Sapphire or Ruby?

On a Personal Note – gr

What is the difference between Pink Sapphire and Ruby? For many of us, the answer is simple – the difference is in the hue. If it is pink, then it is a pink sapphire. If it is red, it is a ruby. But what happens as pink and red merge? Reddish-pink is still sapphire, while pinkish-red is still ruby. But a gem that is color labeled Pink-Red or Red-Pink is what?

Are you one who does not distinguish between pink and red? Do you describe pink as a desaturated red?

In our usual scrolling through LinkedIn posts, Rui Galopim de Carvalho, gemologist and gem education consultant from Portugal posted a wonderful piece on just this question.

Rui Galopim de Carvalho
Gem Education Consultant

Terminology for gem corundum coloured by chromium has always puzzled me for historical, technical and practical reasons.

Historically, all pink to red corundum was classified as ruby, or oriental ruby, sometimes romantically referred to as female ruby (pink) and male ruby (red). The term “pink sapphire” is actually quite recent, reported since the early 20th century and it is now well established in modern gemstone lexicon and trade standards by the World Jewellery Confederation – CIBJO.

Technically, pink can be understood as the same hue, red, but with a different tone (value) and saturation (chroma), meaning, in simpler words, that pink and red are basically the same colour.

In the photo, a c. 4.4 ct pink sapphire from Sri Lanka (?) set on a 19th century gold and diamond insignia of the Order of the Golden Fleece at the Museu Tesouro Real – Palácio Nacional da Ajuda, in Lisboa, Portugal © Rui Galopim de Carvalho.
As expected, in the available historical documentation, this wonderful pink gemstone is described as a ruby and it looks as red as a ruby in the museum’s display.

The practical reasons are several so let me mention a few for faceted stones. The perception of colour within pink to red corundum varies with: the type of illuminant and light environment used for the observation; the cutting style and proportions; the orientation of the optic axis with the table facet and the angle of observation; and with orientation/position of the stone. To add complexity, to clearly separate between pink sapphire and ruby in a laboratory there are a combination of factors involved with established controlled observation conditions and a comparison test with a master set following certain protocols. The interesting fact is that there is no international standard for this, but historically there never was anyway, and it will all be in the eyes of the beholder.

This is a fabulous historical reference on this topic, talking about the historical indifference between pink and red. But today, we do consider pink and red corundum as different gem varieties.

Gem merchants, cutters, and gemologists around the globe struggle with this identification every day. Whether one uses master color tabs or actual master gemstones, any number of light sources, orientations, etc., there will always be those gems that straddle the color fence between pink sapphire and ruby. As we mentioned in the LinkedIn post, there will be those who make their determination based upon whether they are buying or selling. If we are buying, it’s a pink sapphire. If we are selling, it’s a ruby.

Can one argue that a pink sapphire that is almost a ruby, carries more value than a ruby that is almost a pink sapphire? (For example: You label the gem a ruby, and most everyone who sees it is thinking “no, it’s a pink sapphire,” as opposed to a gem labeled pink sapphire where many may say, “it looks like a ruby to me.” Will one sell faster/easier than the other because of how it is labeled?)

The point we should carry away from this, is that the beauty of the gem is not in its label, or the paper that describes it. As Rui points out, and should be true for all gems, is that its value, its beauty are in the eyes of the beholder. – gr

Roskin Gem News Report
Previous articleGem-A Conference: Bringing Together the Greatest Minds in Gemmology
Next articleREVIEW – The Chatham Legacy: An American Story