GRS Pigeon Blood
GRS Pigeon Blood
A proprietary colour designation for rubies meeting the vivid-red standard of GemResearch Swisslab
GRS Pigeon Blood is a colour designation issued by GemResearch Swisslab (GRS), the Lucerne-based gemmological laboratory, for rubies whose hue, tone, and saturation collectively meet the laboratory's proprietary reference for the historically prized pigeon blood standard. When a ruby qualifies, the designation appears as a supplementary notation — commonly rendered as "Pigeon's Blood" — appended to the main GRS report, and it carries measurable weight in the international auction and dealer markets.
What the Designation Describes
GRS defines its Pigeon Blood colour as a vivid red with medium to medium-dark tone and very high saturation, assessed against a set of internal reference stones maintained by the laboratory. The dominant hue is red, with a permissible secondary purple component that must remain subordinate. Fluorescence — typically strong red under long-wave ultraviolet — is considered a contributing factor to the overall face-up appearance, though it is not itself a grading criterion for the colour call. The result is a stone that appears intensely, almost luminously red in daylight-equivalent illumination, with minimal brown or orange modifiers.
Crucially, GRS applies the designation on the basis of colour alone, independent of geographic origin. A Mozambican ruby from the Montepuez deposit can receive the same Pigeon Blood notation as a Burmese stone from Mogok, provided both satisfy the colour benchmark. In practice, however, Burmese and Mozambican rubies account for the overwhelming majority of stones that qualify, reflecting the characteristic chemistry of those deposits — low iron content in Mogok material and strong chromium-driven saturation in Montepuez goods.
Laboratory Report Context
The GRS colour-quality descriptor system places Pigeon Blood at the apex of its ruby colour hierarchy, above designations such as "vivid red" or "red." The notation is issued as an addendum rather than as the primary colour description on the report, and it is accompanied by the laboratory's standard findings on species, variety, geographic origin (where determinable), and treatment status. A ruby bearing both a Burmese origin determination and the Pigeon Blood colour call represents the most commercially sought combination in the GRS report ecosystem.
GRS introduced the formal Pigeon Blood descriptor in the early 2000s, helping to standardise — and commercialise — a term that had previously circulated in the trade as an informal, subjective appellation with no consistent definition. Other major laboratories, notably Gübelin and SSEF, have developed analogous colour-quality designations under their own terminology, though the precise criteria and nomenclature differ between institutions.
Market Significance
The presence of the GRS Pigeon Blood notation on a report has become a recognised value driver at auction and in the wholesale trade. Fine rubies carrying this designation — particularly those also confirmed as Burmese and unheated — have achieved premiums that reflect both the rarity of the colour and the market confidence that a named laboratory standard provides. The designation effectively converts a subjective aesthetic judgement into a documented, transferable credential, which matters considerably when stones change hands across jurisdictions and between buyers who have not personally inspected the gem.
It should be noted that the designation is a colour opinion, not a guarantee of value, and that market premiums fluctuate with supply, demand, and shifting collector preferences. Rubies from Mozambique that qualify for the Pigeon Blood call have, over the past decade, narrowed the price gap with Burmese equivalents, though a premium for Mogok origin typically persists among the most discerning collectors.
Relationship to the Broader Pigeon Blood Concept
The term pigeon blood itself predates any laboratory system by centuries, originating in the Burmese and broader Asian gem trade as a description of the finest Mogok rubies. Its historical meaning was never precisely codified, and different traders applied it with varying thresholds. The GRS designation represents one laboratory's attempt to impose a reproducible standard on this legacy terminology. Collectors and dealers should be aware that a ruby described informally as "pigeon blood" in trade conversation may or may not meet the GRS criterion, and that the laboratory designation and the colloquial term are not interchangeable without qualification.