Ruby, the magnificent red gemstone and birthstone for July, has captivated humanity for millennia with its fiery brilliance. While many think of ruby simply as a red gemstone, connoisseurs know that ruby displays a remarkable range of red hues, each with its own character, value, and appeal. In this comprehensive guide, we'll explore the fascinating spectrum of ruby colors, from the legendary "pigeon's blood" red to delicate pink shades.
The Science Behind Ruby's Red Color
Before diving into the color chart, it's important to understand what gives ruby its distinctive red color. Ruby is a variety of the mineral corundum (aluminum oxide, Al₂O₃), the same mineral that forms sapphires. What distinguishes ruby from sapphire is the presence of chromium (Cr) in the crystal structure. This chromium is responsible for ruby's red color.
The intensity of the red color generally correlates with the amount of chromium present in the stone. However, other factors can influence the final color:
- Iron content: Can make the ruby appear more brownish or purplish
- Titanium content: May contribute to a more purplish hue
- Vanadium content: Can add a purplish or orangish tint
- Light conditions: Ruby's color can appear different under various lighting conditions (daylight vs. incandescent light)
Ruby Color Chart: The Complete Spectrum
Ruby colors range from light pink to deep red, with various undertones and saturation levels. Here's a comprehensive chart of ruby colors from most to least valuable:
| Color Name | Description | Color Sample | Value |
|---|---|---|---|
| Pigeon's Blood Red | Pure, vivid red with a hint of blue, considered the finest ruby color | Highest | |
| Burma Red | Rich red with excellent saturation, slightly less blue than pigeon's blood | Very High | |
| Blood Red | Deep red with excellent saturation, slightly darker than pigeon's blood | High | |
| Crimson Red | Bright red with a slight purplish tint | High | |
| Raspberry Red | Red with a stronger purplish tint | Medium-High | |
| Thai Ruby Red | Darker red with brownish or purplish undertones | Medium | |
| Pinkish Red | Medium-toned red with noticeable pink undertones | Medium | |
| Pink Ruby | Light to medium pink, borderline between ruby and pink sapphire | Lower | |
| Orangish Red | Red with noticeable orange undertones | Lower | |
| Brownish Red | Red with brown undertones, often due to iron content | Lowest |
Note: The color samples above are digital approximations and may not perfectly represent actual ruby colors, which can vary based on lighting conditions, cut, and other factors.
The Legendary "Pigeon's Blood" Ruby
The term "pigeon's blood" has been used for centuries to describe the most coveted ruby color. This poetic description originated in Myanmar (formerly Burma), where some of the world's finest rubies have been mined. But what exactly is "pigeon's blood" red?
Pigeon's blood ruby displays a pure, vivid red color with a hint of blue. The name comes from the supposed similarity to the first drop of blood from a freshly killed pigeon's nose. While this may sound macabre to modern ears, it has become the standard term for describing the finest ruby color in the gemological world.
In 2015, the Gemological Institute of America (GIA) formalized the "pigeon's blood" designation in their ruby reports, defining specific color parameters that a ruby must meet to receive this prestigious description. This standardization helps ensure consistency in the marketplace.
Factors Affecting Ruby Color
Several factors influence the appearance of a ruby's color:
1. Hue
Hue refers to the basic color of the ruby. The primary hue of ruby is red, but secondary hues can include purple, orange, or pink. The most valuable rubies have a pure red hue with minimal secondary colors, though a slight purple or pink secondary hue can be acceptable in fine stones.
2. Tone
Tone describes how light or dark the color appears. The most valuable rubies typically have a medium to medium-dark tone—not so dark that they appear blackish and not so light that they appear pink. The ideal tone allows for vibrant color while maintaining good brilliance.
3. Saturation
Saturation refers to the intensity or purity of the color. High-saturation rubies display vivid, intense color, while low-saturation stones appear more grayish or brownish. The most valuable rubies have strong saturation with vibrant color.
4. Distribution
Color distribution describes how evenly the color is spread throughout the stone. Ideally, a ruby should have uniform color distribution without obvious color zoning (areas of different color or intensity).
5. Fluorescence
Many fine rubies exhibit red fluorescence under ultraviolet light, which can enhance their color appearance in daylight. This natural fluorescence can make a ruby appear to "glow" from within, adding to its beauty and value.
Ruby Color by Origin
The geographic origin of a ruby often influences its color characteristics:
Myanmar (Burma)
Burmese rubies, particularly those from the famed Mogok Valley, are renowned for their "pigeon's blood" red color. These rubies typically display a pure red with a hint of blue and strong red fluorescence that enhances their appearance. Burmese rubies are generally considered the finest in the world and command premium prices.
Thailand
Thai rubies typically have a darker, more garnet-like red with brownish or purplish undertones. They generally have less fluorescence than Burmese rubies, resulting in a less "glowing" appearance. However, they often have excellent clarity and can be found in larger sizes.
Mozambique
Since their discovery in the early 2000s, Mozambique rubies have become increasingly important in the market. The finest Mozambique rubies can display a rich, slightly purplish-red color that approaches the quality of Burmese stones. They often have good transparency and fewer inclusions than rubies from other sources.
Madagascar
Madagascar produces rubies with a range of colors, from pinkish-red to deep red. Some high-quality Madagascar rubies can rival Burmese stones in color, though they may have different inclusion characteristics.
Vietnam
Vietnamese rubies, particularly those from Luc Yen, can display an intense red color similar to fine Burmese material. Some Vietnamese rubies have been described as having a "traffic light red" color—bright and vibrant.
The Pink-Red Boundary: When Is It Ruby vs. Pink Sapphire?
One of the most debated topics in colored gemstones is the distinction between ruby and pink sapphire. Both are varieties of corundum colored by chromium, but ruby is defined as the red variety, while pink sapphire is... well, pink.
The boundary between ruby and pink sapphire is somewhat subjective and has varied historically and geographically. In some traditions, particularly in Southeast Asia, even light pink corundum may be considered ruby. In Western markets, however, the distinction is generally more strict.
Most gemological laboratories use specific color parameters to distinguish ruby from pink sapphire, though these standards aren't universally identical. Generally, if the dominant color is red (even if it's a lighter red), the stone is classified as ruby. If the dominant color is clearly pink, it's classified as pink sapphire.
This distinction matters commercially because rubies typically command higher prices than pink sapphires of similar quality, even when the visual difference is subtle.
Color Treatments in Rubies
It's important to note that many rubies on the market have been treated to enhance their color. Common treatments include:
Heat Treatment
The most common and widely accepted treatment, heating can improve a ruby's color and clarity by dissolving "silk" (rutile inclusions) and altering the chromium content. Heat treatment is permanent and stable.
Diffusion Treatment
This process involves heating the ruby with color-causing elements (like chromium) that diffuse into the outer layer of the stone, creating a more intense color. This treatment may only affect the surface layer and can be detected by gemological testing.
Glass Filling
Some rubies with fractures are filled with lead glass to improve their appearance and durability. This treatment can significantly affect value and requires special care, as the glass filling can be damaged by heat, chemicals, or ultrasonic cleaning.
Untreated rubies with fine color are extremely rare and command significant premiums over treated stones of similar appearance.
How to Evaluate Ruby Color When Purchasing
When shopping for a ruby, consider these tips for evaluating color:
- Examine under different lighting: View the ruby under daylight-equivalent lighting, incandescent lighting, and if possible, natural daylight to see how the color changes.
- Look for color zoning: Rotate the stone and look for areas of different color intensity or hue.
- Consider size: Color typically appears more intense in larger stones, so smaller rubies may need to have exceptional color to appear vibrant.
- Check for windowing: Poor cutting can cause a "window" in the center of the stone where light passes straight through rather than reflecting back, creating a washed-out area.
- Ask about treatments: Always inquire whether a ruby has been treated to enhance its color and, if so, by what method.
- Request certification: For significant purchases, obtain a gemological report from a reputable laboratory like GIA, which will specify color characteristics and any treatments.
Conclusion: The Enduring Allure of Ruby Red
The rich, vibrant red of a fine ruby continues to captivate gem lovers worldwide. From the legendary "pigeon's blood" red of Burmese rubies to the varied hues from deposits around the world, ruby's color spectrum offers something to appeal to every taste and budget.
Understanding the nuances of ruby color not only helps in making informed purchasing decisions but also deepens appreciation for these magnificent gemstones. Whether you're drawn to the intense red of a classic Burmese ruby or prefer the slightly purplish hues of stones from other origins, the fiery brilliance of ruby—July's birthstone—continues to symbolize passion, protection, and prosperity across cultures and throughout time.
When selecting a ruby, remember that while color is the most important value factor, the best stone is ultimately the one whose color speaks to you personally. After all, the magic of gemstones lies not just in their monetary value but in the joy and meaning they bring to their owners.
Written by Emily Richardson
Founder & Lead Gemologist with over 15 years of experience in the jewelry industry. Emily has traveled to mining regions across five continents and holds a Graduate Gemologist certification from the GIA.
