"Pigeon's Blood" is considered as the best color for rubies. In Guild grading and origin report, Pigeon's Blood is represented by [Vivid Red*], [Vivid to Deep Red*] or [Vivid to Intense Red*] and commented as *Trade Name: Pigeon's Blood.

 In the ruby color grading system of the Guild Gem Lab, "Pigeon's Blood" is not limited to any specific origin. Any ruby with high saturation and appropriate tone, regardless of where it is produced, has the potential to receive the "Pigeon's Blood" rating.

Figure 1: Vivid Red (left) and Pigeon's Blood (right)

Development History

Guild Gem Lab has always focused on the testing of colored gemstones, especially the enhancement treatments, color grading, and origin research of emeralds, rubies, and sapphires.

Announcement: In 1996, GRS was the first to use "Pigeon's Blood" to define rubies that reached a specific color grade. In June 1998, the first "Pigeon's Blood" ruby certificate appeared on Lot 140 at Sotheby's London, a 1.35-carat ruby ring judged as "Pigeon's Blood" by GRS.

Standardization: Currently, there is no unified international color grading standard for rubies, and major laboratories have their own color grading systems that are constantly being refined and updated. Guild Gem Lab has conducted decades of research on rubies, comprehensively considering factors such as origin, color, and clarity. It issues the commercial name "Pigeon's Blood" for rubies that meet the highest color rating criteria, which falls within the Vivid Red and Deep Red categories of the Guild Ruby Color Grading System. In accordance with its consistent rigorous approach and respect for high-quality colored gemstones, "Pigeon's Blood" in the Guild Ruby Color Grading System is not limited to any specific origin. Any ruby with high saturation and appropriate tone has the potential to receive the top-level evaluation of "Pigeon's Blood."

Marketization: "Pigeon's Blood" has a long history in the ruby trade, initially representing top-quality rubies from the Mogok mining area in Myanmar. Now, regardless of origin, "Pigeon's Blood" has gone global and conquered generations of colored gemstone consumers, becoming the best synonym for top-quality rubies. According to the 2021 Guild Colored Gemstone Market Report, the proportion of rubies rated as "Pigeon's Blood" was 80.5% in 2020 and 77.5% in 2021. This indicates that the term has been accepted and appreciated by end-consumers worldwide and has become an international standard. Almost all international gemstone laboratories recognize and use "Pigeon's Blood" to describe the color of top-quality rubies.

Figure 2: Statistics on the Number of Ruby Samples Received by Guild Gem Lab from 2017 to 2021. 

Data Source: Guild Gem Lab

Grading System

Ruby is a gem-quality corundum with red as the dominant hue, often accompanied by a slight purple or orange tint. The presence of chromium gives ruby its vivid and intense red color. In terms of hue, tone, and saturation, the color of rubies can be divided into four categories by GUILD:

In the ruby color grading system of Guild Gem Laboratory, "Pigeon's Blood Red" is not limited by origin. Any [Vivid Red*], [Vivid to Deep Red*] or [Vivid to Intense Red*] ruby with high saturation and appropriate tone has the possibility of obtaining the rating of "Pigeon's Blood Red". It is worth noting that rubies with any of the following characteristics will not receive the rating of "Pigeon's Blood Red":

(1) Having obvious secondary hues, such as purple hues, orange hues, etc.;
(2) Having obvious quality problems, such as low clarity, obvious color zones, windowing, etc.;
(3) Having low saturation and dark brightness;
(4) Having undergone artificial treatment methods, such as glass filling, surface coating, dyeing, etc.;
(5) Being synthetic rubies