Pigeon blood red ruby from Vietnam

By Dr. M.S. Krzemnicki, first published in Facette 29 (May 2024)

Figure 1: 2.10 ct ruby from Vietnam (left), colour grading of rubies at SSEF (right). Photos: SSEF.

Recently, a beautiful Vietnamese ruby of 2.10 ct and vivid red colour was submitted to SSEF for testing. Microscopic observations and chemical trace element analysis confirmed its Vietnamese origin and our colour grading protocol revealed that this stone was well fitting to be called ‘pigeon blood red’ based on SSEF standards.

Although most rubies which have been classified by SSEF as ‘pigeon blood red’ are of Burmese origin (Mogok or Mong Hsu), we have seen in the past also rubies from other gem deposits such as Vietnam – as the above-described gem -, Tajikistan, and even East Africa which were fitting to be called ‘pigeon blood red’.

The SSEF applies strict criteria to classify a ruby as ‘pigeon blood red’. Apart from the saturated and vivid red colour which is compared with a set of ruby master stones, the ruby must be untreated (e.g. no indications of heating and/or clarity modification) and show a strong red fluorescence under UV light. It is important to know that the geographic origin is not a criterion at SSEF and therefore the term ‘pigeon blood red’ is applied and mentioned on our report if the listed criteria are met.

A detailed description of the criteria for ‘pigeon blood red’ rubies (and ‘royal blue’ sapphires) is found on our SSEF website (https://www.ssef.ch/pigeon-blood-red-royal-blue/) and in SSEF Facette 2016 (pages 8-9).