GRS-type “Pigeon Blood” Ruby


This color term has far-reaching pedigrees and was traditionally used to describe the finest colors found in Burmese (Myanmar) ruby. GRS first introduced the color term GRS-type “pigeon blood” onto the market in 1996, creating a market standard for the trade, auction houses, and end-users.


GRS-type "pigeon blood" Type 1 describes rubies displaying colors ranging from medium-strong to strongly saturated vivid red hues ( high intensity and low tone) and exhibiting medium to strong fluorescence when exposed to UV light (365nm).

In 2012 GRS introduced the "pigeon blood" Type 2 color term for rubies displaying the correct vivid red color but producing less than medium-strong fluorescence. Qualifying rubies receive an appendix to the GRS gemstone report which includes the following comment:

“This vivid red Mozambican ruby is reminiscent in color saturation of a GRS-type “pigeon blood” ruby (without strong fluorescence).”

Rubies qualifying for the GRS-type "pigeon blood" designation may be found in various global sites like Burma (Myanmar), Mozambique or Madagascar etc.

Type 2 GRS-type “pigeon blood” ruby ring from Madagascar, 4.04 ct. GRS2009-031560.


The first auction house publication citing the use of the GRS term "pigeon blood" was Sotheby’s Important Jewels London, June 1998 (Lot 140, GRS number GRL9804015). Today the term GRS-type "pigeon blood" has become an industry-wide standard that has been adapted by other laboratories as well.

Auction References:

  • A ring featuring a 20.03 ct Mozambican ruby at an international auction house in Hong Kong, 2013 accompanied by a GRS-type “pigeon blood” report.
  • A necklace featuring 48 unheated Burmese pigeon blood rubies from Mogok and Mong Hsu at Christie's sold for US$13M in 2015 accompanied by a GRS-type "pigeon blood" report.
Necklace featuring 21 unheated Type 1 GRS-type "pigeon blood" rubies (42.24 ct total weight) from Mozambique. GRS2016-028033. GRS Collection.


Ruby qualifying for GRS-type “pigeon blood” must contain a relatively high chromium (Cr) content of approx. 0.3 to 0.5 wt-% (or higher) and none or very low to medium iron (Fe); while the ratio of Cr/ Fe is greater than 1 (individual face-up color and fluorescence-corrections are also applied).

Type 1 - GRS-type "pigeon blood" applies to all marble deposit ruby. They generally exhibit a medium-strong to strong fluorescence when exposed to UV light (365nm) due to their high chromium (Cr) concentration and low iron content (Fe). Some non-marble deposit ruby with subsequently higher iron concentrations may qualify as Type 1 - GRS-type “pigeon blood”, providing they exhibit a medium-strong to strong fluorescence.

Type 2 - GRS-type “pigeon blood” applies to all other rubies that properly face up in appearance but display a medium or less fluorescence when exposed to UV light (365nm).

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Type 1: GRS-type "pigeon blood" Ruby
Type 2: GRS-type "pigeon blood" Ruby

The GRS-type “pigeon blood” label is not granted for:

  • Rubies with dominant quality issues such as apparent color zoning, windowing or disturbing inclusions
  • Beryllium-treated rubies / H(Be)
  • Lead-glass-filled rubies
  • Rubies with more than minor residues from heating H(c) and H(d)
  • Synthetic rubies

Sources from which GRS- type “pigeon blood” rubies may originate from:

  • Afghanistan
  • Burma (Myanmar)
  • Madagascar
  • Mozambique
  • Tajikistan
  • Tanzania
  • Vietnam and others
Example of a non-Burmese ruby exhibiting strong fluorescence.
This particular stone is a 8.35 ct unheated ruby from Tajikistan. GRS Collection. GRS2013-078486.

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