The month of July is traditionally associated with the vibrant red gemstone, the ruby. Revered for its intense color and remarkable durability, the ruby has been a symbol of passion, protection, and prosperity for centuries. As one of the four cardinal gemstones, alongside diamond, sapphire, and emerald, it holds a distinguished place in both historical lore and modern jewelry. This article explores the rich history, geological origins, gemological properties, and cultural significance of the ruby, the celebrated birthstone of July.
History and Lore
The history of the ruby is as deep and compelling as its crimson hue. Its name derives from the Latin word rubeus, meaning red. For millennia, this gemstone has been associated with the planet Mars due to its color, leading ancient cultures to believe it possessed the power of protection and vitality.
Historical records and archaeological findings indicate that rubies have been mined and traded for over two millennia. One of the earliest known sources was in the Mogok region of Myanmar (formerly Burma), a source that has been legendary for its high-quality rubies for centuries. The stones from this region were highly prized by Chinese nobility and the courts of Indian maharajas, who adorned their crowns, weapons, and jewelry with rubies, believing they would bring good fortune and ward off evil.
In the Middle Ages, rubies were considered more valuable than diamonds. European royalty and the church held them in high esteem, associating them with the blood of Christ and the power of life itself. A popular belief held that a ruby would change color or become dull if its owner was in danger, serving as a protective talisman. This belief in the stone’s protective qualities persisted for centuries, making it a favored gem for warriors and travelers.
The journey of the ruby to its modern status as a July birthstone is more recent. The concept of birthstones is largely attributed to the Breastplate of Aaron described in the Old Testament, which featured twelve stones representing the twelve tribes of Israel. Over time, these stones were linked to the twelve signs of the zodiac and, later, to the months of the year. The modern list of birthstones was standardized in 1912 by the American National Association of Jewelers (now Jewelers of America). This list, which has been updated only slightly since, officially named the ruby as the birthstone for July, solidifying its place in contemporary culture.
Geological Formation and Sources
Rubies are a variety of the mineral corundum, an aluminum oxide (Al₂O₃). Their red color is caused by trace amounts of the element chromium (Cr³⁺) substituting for aluminum in the crystal lattice. The presence of chromium is what distinguishes a ruby from other colors of corundum, such as sapphire. For a stone to be classified as a ruby, the color must be a "vivid red to slightly purplish red." The concentration of chromium directly influences the intensity of the color; higher chromium levels yield a more vibrant red, though they can also introduce a purplish tint.
The formation of natural rubies occurs under specific and extreme geological conditions. They are typically found in metamorphic rocks, formed under high temperatures and pressures. A common host rock is marble, which results from the metamorphism of limestone. This process allows chromium to be incorporated into the growing corundum crystals. Rubies can also form in basalts, where aluminum and silicon are abundant, and chromium is supplied by the surrounding rocks.
The primary sources of natural rubies are geographically concentrated in a few key regions:
- Myanmar (Burma): The Mogok and Mong Hsu regions in Myanmar are historically the most famous sources for the world's finest rubies. Burmese rubies are renowned for their intense, vibrant red color often described as "pigeon's blood," a term for the most prized pure red with a slight bluish undertone. The geology of this region, particularly the marble deposits, is ideal for producing high-quality gemstones.
- Thailand: The Chanthaburi and Trat provinces in eastern Thailand have been a major source of rubies for decades. Thai rubies often have a slightly darker, more brownish-red or purplish hue compared to Burmese stones. The mining operations in Thailand are significant, and the country has long been a central hub for the cutting and trading of rubies.
- Vietnam: Rubies from the Luc Yen and Quy Chau districts in Vietnam have gained prominence in recent decades. Vietnamese rubies often exhibit a rich red to purplish-red color, sometimes rivaling the quality of Burmese stones.
- Other Sources: Smaller deposits of rubies are found in Afghanistan, Pakistan, Sri Lanka (where they are often found alongside sapphires), and in Africa, particularly in Tanzania and Kenya. African rubies can vary in color, sometimes showing a more orange or pinkish cast.
The mining of rubies is often conducted on a small to medium scale, involving both artisanal and commercial operations. The process is labor-intensive, as the rough crystals are typically small and must be carefully extracted to avoid damage.
Gemological Properties
The ruby is prized not only for its color but also for its exceptional physical properties, which make it one of the most durable gemstones suitable for jewelry.
- Chemical Composition: Ruby is a variety of corundum, with a chemical formula of Al₂O₃. The red color is a result of trace impurities, specifically chromium (Cr³⁺).
- Crystal System: Trigonal.
- Hardness: On the Mohs scale of mineral hardness, ruby scores a 9. This makes it second only to diamond in hardness, meaning it is highly resistant to scratching and abrasion. This durability is a key reason why rubies are often used in engagement rings and other jewelry that is worn daily.
- Specific Gravity: The specific gravity of ruby typically ranges from 3.95 to 4.10. This measurement helps gemologists distinguish it from other similar-looking stones.
- Refractive Index: The refractive index of ruby falls between 1.760 and 1.770. This property is responsible for the stone's brilliance and light return.
- Pleochroism: Ruby exhibits strong to weak pleochroism, meaning it can show different colors when viewed from different crystal directions. In ruby, the colors are typically red and a reddish-orange or purplish-red. This characteristic is an important diagnostic tool for gemologists.
- Inclusions: Natural rubies almost always contain inclusions (internal features). The type and pattern of inclusions can help determine the stone's origin and whether it has been treated. For example, fine silk (minute rutile needles) is a common inclusion in Burmese rubies and can sometimes enhance the stone's color by diffusing light. While clarity is valued, a completely flawless natural ruby is exceedingly rare. In the trade, some inclusions are accepted as long as they do not significantly detract from the stone's beauty or durability.
The table below summarizes the key gemological properties of ruby:
| Property | Description |
|---|---|
| Mineral | Corundum |
| Chemical Formula | Al₂O₃ (with Cr³⁺ impurities) |
| Color | Red to slightly purplish red |
| Hardness (Mohs) | 9 |
| Crystal System | Trigonal |
| Refractive Index | 1.760 – 1.770 |
| Specific Gravity | 3.95 – 4.10 |
| Pleochroism | Weak to strong; red and reddish-orange/purplish-red |
Symbolism and Metaphysical Beliefs
Beyond its physical beauty, the ruby is steeped in symbolism and has been attributed with various metaphysical powers throughout history. These beliefs, while not scientifically proven, contribute to the gemstone's mystique and cultural importance.
In many ancient cultures, the ruby was considered the "King of Gems." Its red color, reminiscent of blood and fire, led to associations with life force, passion, and energy. In Vedic astrology, which has influenced Indian culture for millennia, the ruby is linked to the Sun, a planet representing power, authority, and vitality. Wearing a ruby was believed to bring good health, success in competitions, and a boost to one's confidence and leadership qualities.
The stone was also a powerful talisman for protection. Medieval Europeans believed that a ruby could protect its wearer from plague, fever, and bad dreams. In some traditions, it was thought that a ruby would change color to warn of impending danger or misfortune. This protective quality made it a popular gem for soldiers and those embarking on long journeys.
In terms of emotional and spiritual symbolism, the ruby is often associated with intense love and passion. It is considered a stone of love, representing the heart's desires and the strength of romantic relationships. Giving a ruby as a gift is seen as a profound expression of love and devotion. Furthermore, it is believed to stimulate the heart chakra, promoting feelings of compassion, generosity, and courage.
While these metaphysical beliefs are part of the gemstone's rich cultural tapestry, they are not recognized by modern gemology. The value and significance of a ruby in the contemporary market are determined by its physical properties: color, clarity, cut, and carat weight.
Care and Cleaning
Given its exceptional hardness and durability, the ruby is a relatively easy gemstone to care for, making it an excellent choice for everyday jewelry. However, proper maintenance is essential to preserve its beauty and integrity over time.
- Cleaning: The ruby can be safely cleaned using warm water, a mild soap, and a soft brush (such as a toothbrush). Gently scrub the stone and its setting to remove any dirt, oil, or lotion buildup. Rinse thoroughly with clean water and dry with a soft, lint-free cloth. Avoid using harsh chemicals, such as bleach or ammonia, as they can damage the metal setting or any treatments the stone may have undergone. Ultrasonic cleaners are generally safe for untreated rubies but should be avoided for stones that have been fracture-filled, as the vibrations can cause the filler to dislodge. Steam cleaning is also not recommended for treated rubies.
- Storage: When not being worn, store ruby jewelry separately from other pieces to prevent scratching. Although ruby is very hard, it can still be scratched by diamonds and other rubies. A soft pouch or a compartmentalized jewelry box is ideal.
- Durability Considerations: While ruby has a hardness of 9, it does have one direction of cleavage, though it is not perfect. This means that a sharp, hard blow at a specific angle could potentially cause the stone to chip or break. Therefore, it is advisable to remove ruby jewelry during activities that could subject it to impact, such as heavy manual labor, sports, or gardening.
By following these simple care instructions, a ruby can remain a stunning and vibrant gemstone for generations, serving as a lasting heirloom and a testament to its enduring appeal.
Conclusion
The ruby stands as a gemstone of unparalleled beauty and significance. From its ancient origins in the marble mountains of Myanmar to its modern status as the cherished birthstone of July, it has captivated humanity with its fiery red hue and remarkable durability. Its geological formation, requiring a rare combination of aluminum, oxygen, and trace chromium, results in a gemstone that is both scientifically fascinating and visually stunning. The ruby's properties—its hardness, brilliance, and unique inclusions—not only define its value in the gemological world but also make it a practical and enduring choice for fine jewelry. Steeped in a rich history of lore and symbolism, it continues to represent passion, protection, and power. For those born in July, the ruby is more than a beautiful gem; it is a personal talisman, a piece of Earth's fiery heart, and a timeless symbol of life's most intense emotions.