January’s birthstone is the garnet, a gemstone that comes in a variety of colors from the deep red of rubies to shades of orange, green, purple, yellow, and even black. Garnets have been prized since ancient times and used in jewelry and ornamental objects for thousands of years. But what exactly is a garnet and how does it differ from other gemstones like rubies? Here’s a look at the January birthstone and why it can encompass both garnets and rubies.
What is a Garnet?
Garnets are a group of silicate minerals that share a common crystal structure and chemical composition but can vary widely in color. The name “garnet” comes from the Latin “granatum” meaning “seed” because of the gemstone’s resemblance to the bright red seeds of a pomegranate. There are many varieties of garnet based on their precise chemical composition and ratios of elements like calcium, magnesium, iron, and manganese. The six main types of garnet are:
- Pyrope – magnesium aluminum silicate, typically red
- Almandine – iron aluminum silicate, deep red to purple
- Spessartine – manganese aluminum silicate, orange to red-brown
- Grossular – calcium aluminum silicate, yellow, green, brown, or red
- Andradite – calcium iron silicate, green, yellow, brown, red, or black
- Uvarovite – calcium chromium silicate, bright green
The mixture of these garnet varieties and trace elements accounts for the wide spectrum of colors they can display. While many people think of red gems when they hear “garnet,” they can range from deep brownish-red and purplish-red to shades of orange, green, and yellow.
What are Rubies?
Rubies are a rare and coveted variation of the mineral corundum, composed of aluminum oxide. Corundum is the second hardest natural mineral after diamond. The word “ruby” comes from the Latin “ruber” meaning red. The distinctive red color of rubies is caused by trace amounts of the element chromium. The most prized rubies have a deep pigeon-blood red hue. Other varieties of corundum come in different colors, like sapphires which get their blue color from traces of iron and titanium.
| Garnet | Ruby |
|---|---|
| Made of many silicate minerals | A type of corundum (aluminum oxide) |
| Colors include red, purple, orange, yellow, green, brown, black | Known specifically for red color |
| Less rare and valuable than rubies | Very rare and valuable |
| Softer than rubies (6.5-7.5 on Mohs scale) | Extremely hard (9 on Mohs scale) |
| Found in many parts of the world | Found mainly in a few sources like Myanmar, Sri Lanka, Thailand |
Are Rubies a Type of Garnet?
Even though rubies and garnets can have similar red hues, rubies are not a type of garnet. As explained above, they have completely different chemical compositions, structures, hardness, rarity, and origins. The red garnets like pyrope and almandine have a similar appearance to rubies but are separate and distinct minerals. While garnets belong to the silicate class of minerals, rubies are a variety of corundum.
The confusion sometimes arises because lesser quality rubies are often called “cape rubies.” These stones are usually almandine or pyrope garnets, not true rubies. They were named this way because traders brought them to Europe from India via the Cape of Good Hope. But while they resemble rubies, they are not actually part of the corundum family.
Why are Both Garnets and Rubies January Birthstones?
January’s birthstone is listed as both the garnet and the ruby by jewelry and gemstone organizations because the deep red variety of garnet has such a similar look to true ruby gemstones. Even though rubies technically aren’t garnets, they fit with the red theme of the month. The modern January birthstone list created by the American National Association of Jewelers in 1912 was the first to include both garnet and ruby.
Previously, ancient and medieval birthstone lists assigned different stones to each month. Garnet was designated for January at least as far back as the first century AD, while ruby was linked to July. But due to their shared red color, jewelers decided to designate both garnet and ruby for January. This highlights that while their composition varies, their appearance is similar enough to group them under January’s birthstone.
Some key differences despite the likeness in red color:
- True rubies are far rarer and command higher prices than similar colored garnets.
- Garnets exhibit more variety in their red hues including darker brownish-reds.
- The hardness and brilliance of rubies exceeds that of garnet.
| Ruby | Garnet |
|---|---|
| Much rarer than garnets | More common and affordable than rubies |
| Ideal “pigeon blood red” color | Red color more brownish/purplish |
| Very hard – 9 on Mohs scale | Softer – 6.5-7.5 on Mohs scale |
| Brilliant refractive quality | Less brilliance than rubies |
Meaning and Symbolism
Beyond the shared red color, garnets and rubies have different traditional meanings and symbolism.
Garnets were believed to provide protection in travel and ward off nightmares. Their red color was thought to illuminate the night and prevent anger, jealousy, and unfaithfulness. Garnets are also associated with love, passion, energy, and inspiration.
Rubies were considered more valuable and mystical, with connections to nobility, vitality, blood, and passion. In Burmese tradition, rubies were thought to contain a drop of the heart’s blood of the earth. Ancient Hindus believed rubies granted immortality, health, and wisdom. Rubies also symbolize love, commitment, and integrity.
Geographic Sources
While garnets are found all over the world, true rubies have rare and specific sources. The most significant deposits of garnets are in India, the United States, South Africa, Australia, and parts of Asia. Some key sources of natural rubies include:
- Myanmar (Burma): The Mogok mining region in Myanmar has produced exceptional “pigeon blood” rubies, but mining controversies have reduced supply.
- Sri Lanka: Historic source mined for over 2,000 years, known for deep red rubies with blue fluorescence.
- Thailand: Significant source for rubies with purity and vivid coloring.
- Vietnam: Luc Yen mines produce beautiful red rubies often likened to Burmese quality.
- Afghanistan: Jegdalek mine yields rare pinkish-red rubies.
- Greenland: Crystallized rubies found in igneous rock, usually small but vibrant red.
Enhancements
Due to their rarity, most rubies on the market have been treated to improve their color and clarity. Fracture filling with lead glass and heat treatment to remove imperfections are common enhancement techniques. Synthetic rubies have also been manufactured since the late 19th century to increase supply.
While garnets are sometimes enhanced to intensify their color, most garnets are untreated. However, some green garnets called demantoid receive radium treatment to make them more brilliant and remove yellow tints.
Prices
High quality natural rubies fetch extremely high prices, sometimes exceeding the cost of diamonds on a per carat basis. Large fine rubies can cost tens of thousands to millions of dollars per carat. In 2015, a 25.59 carat “Sunrise Ruby” sold in Geneva for over $30 million.
Garnets range much lower in price from $10-$800 per carat depending on their color, variety, and quality. However, demantoid garnets are exceptions, ranging from $2,000-10,000 per carat for vivid green stones.
| Ruby Price Range | Garnet Price Range |
|---|---|
| $1,000-$10,000+ per carat | $10-$800 per carat |
| Rare exception: $1 million+ per carat | Exception: Demantoid $2,000-$10,000 per carat |
Jewelry Uses
The hardness of rubies makes them suitable for almost any type of jewelry, including rings, earrings, bracelets, and necklaces. Their exceptional brilliance means rubies are usually cut into classical rounded shapes to maximize their sparkle. Due to their cost, small rubies are often used as accent stones in jewelry.
While softer than rubies, most garnets are still hard enough for jewelry. However, some care should be taken to prevent damage or abrasion. Garnets are popular for all types of jewelry from everyday pieces to elaborate designer collections. Smaller garnets can provide bright pops of color around diamonds for a more affordable red accent.
How to Tell Difference
It takes a skilled gemologist to conclusively identify garnets and rubies, but here are some ways an average person can spot the differences:
- Look at color in natural and lamp light. Rubies exhibit a more pure, intense red in both.
- Check for natural imperfections like inclusions and fractures. These are very rare in rubies but more common in garnets.
- Consider the price. Genuine rubies over 1 carat cost significantly more than similar sized garnets.
- Evaluate hardness and toughness. Garnets are softer and more prone to chipping or abrasion.
- Observe brilliance and refractive qualities. True rubies have exceptional fire and light reflection.
Advanced testing like chemical analysis, spectroscopy, and microscopy can definitively determine a stone’s specific properties and identification as garnet or ruby, but is not practical for casual use.
Popular Ruby and Garnet Gemstones
Some of the most famous rubies and garnets give a glimpse of their full potential:
- Rosser Reeves Star Ruby – 138.7 carat cabochon ruby displaying asterism or star light effect.
- Patricia’s Ruby – 620 carat Burmese ruby displayed at New York’s American Museum of Natural History.
- Edwardes Ruby – 167 carat cabochon from Sri Lanka, set in Medieval Imperial State Crown.
- Chhatrapati Manik – 380 carat carved ruby found in the Indian royal treasury.
- Rhodolite – Combination of pyrope and almandine garnets, raspberry red color.
- Tsavorite – Brilliant green garnet variety discovered in East Africa.
- Mandarin Spessartine – Rare orange-yellow spessartine garnets.
Conclusion
While garnets and rubies are separate types of minerals, their red color means both qualify as January birthstones. Garnets offer a wide spectrum of red, purple, orange, yellow, green, brown, and black. True rubies are extremely rare and valuable red corundum prized for their pure coloring and brilliance. Their similarities mean garnets can provide a more affordable alternative to costly rubies. But despite some overlapping uses in jewelry, their composition, hardness, value, and sources clearly distinguish the January birthstones of garnet and ruby.
