What are "Crimson Red" rubies: a newly coined term by the Gübelin Gem Lab

Most rubies are mined in various countries such as Myanmar (Burma), Thailand, Vietnam, Afghanistan, Pakistan, Sri Lanka and Tanzania. The largest deposits of high-quality rubies were found in Myanmar, also known as Burma, which has been the primary source of the finest rubies for centuries accounting 90% of the world’s supply at one point in time. However in recent years the pendulum has begun to swing the other way as new deposits of high quality rubies have been discovered. Other countries such as Madagascar, Mozambique, and Malawi have also become significant producers of rubies in recent years. Today, according to recent estimates, Mozambique supplies around 80% of the world's production of high-quality rubies. This is due to the discovery of rich ruby deposits in the Montepuez area in 2008.

Till date the best quality rubies were given the moniker “Pigeon Blood”. "Pigeon blood" is a term used to describe the color of high-quality rubies. It refers to a deep, rich red color that is often described as being similar to the blood of a pigeon. Since 90% of rubies originated from Burma it referred largely to rubies mined in Burma more specifically the Mogok region. Now with rubies being discovered in other parts of the world the term “pigeon blood” started to be used as an all-encompassing term for the top-quality rubies irrespective of whether or not they were from Burma.

It is important to note that rubies like all other natural gemstones have slight differences in their characteristics depending on their country of origin where they have been mined. We can go even further to say that differences might be present between mine to mine even in the same country. Gemstone traders have been using certain terms to describe the colors of certain gemstones for centuries such as “Argyle Pink”, “Chocolate Diamonds”, and “Pigeon Blood Rubies”, these trade phrases take into account not only hue, but also quality and rarity factors such as transparency, origin and the absence of treatments. And there has been a pressing need within the trade for another term to describe high quality rubies found outside Burma.

The Gübelin Gem Lab from Switzerland, established 100 years ago in 1923, has been studying the evolution of these trade color terms. In 2005, the lab established a definition and policy for "royal blue" sapphires and "pigeon blood red" rubies, both of which were based on the highest quality gems from Burma. However, as most rubies on the market now originate outside of Burma and lack the defining characteristics of "pigeon blood red," the Gübelin Gem Lab has coined a new trade color term: "Crimson Red." This term is used to describe rubies that have the ideal color and quality, but with a different fluorescence criterion. To qualify as "Crimson Red," a ruby must have the correct hue, saturation, and tone, be evenly distributed across the stone, be untreated and have a cut that produces a lively brilliance. Additionally, it must have little to no fluorescence in short-wave UV light (something commonly found in pigeon blood rubies). These criteria must be strictly adhered to, and therefore only a small percentage of high-quality untreated rubies will ever meet them. It is expected to be introduced on all certificates being issued after February 2023 for rubies that meet these strict guidelines. “Crimson Red” is expected to become an additional valuable tool for both the jewelry and gemstone trade and the general public to distinguish the rare and extraordinary gems in the market.