For centuries, the gemstones associated with each month of the year have evolved, reflecting shifting cultural preferences, marketing trends, and discoveries of new and remarkable gems. While many birthstone associations are deeply rooted in history, some are relatively recent additions. Spinel, a gemstone celebrated for its vibrant colors and brilliance, exemplifies this evolution. Officially recognized as a modern birthstone for August in 2016 by both the American Gem Trade Association and Jewelers of America, spinel boasts a fascinating history and a growing presence in the world of fine jewelry. This article will explore the history, geological origins, gemological properties, symbolism, and care of this captivating gemstone.
History and Lore
The story of spinel is often intertwined with that of ruby. For centuries, vibrant red spinels were mistaken for rubies, particularly those found in the ancient mines of Burma (Myanmar). This misidentification is understandable, as spinel and ruby share a similar crystal structure and can exhibit remarkably similar hues. Notably, the famous “Black Prince’s Ruby,” a prominent gemstone in the British Crown Jewels, is, in fact, a large, deep-red spinel.
While not always recognized as a distinct gem, spinel has a long history of use in jewelry. Ancient texts do not specifically identify spinel as a separate stone, but its presence in historical jewelry suggests it was valued for its beauty. The gem’s formal recognition as a distinct mineral didn’t occur until 1783, when Jean-Baptiste Romé de l'Isle differentiated it from corundum (ruby and sapphire) based on differences in crystal structure and hardness.
The designation of spinel as an official August birthstone is a more recent development. Prior to 2016, August was represented by peridot, sardonyx, and onyx. The addition of spinel broadened the options for those born in August, offering a vibrant and increasingly popular alternative. This addition reflects a growing appreciation for spinel’s unique qualities within the gemological community and among jewelry enthusiasts.
Geological Formation and Sources
Spinel forms in metamorphic rocks, particularly those subjected to high temperatures and pressures. It is often found in association with other gemstones, such as ruby and sapphire, in marble deposits. Spinel also occurs in alluvial deposits, where it has been eroded from its original source and carried by water.
Historically, significant spinel deposits were located in Burma (Myanmar), where the gem was often confused with ruby. Today, spinel is also mined in Sri Lanka, Vietnam, Thailand, and Tajikistan. More recent discoveries have yielded fine spinel crystals in Tanzania, Madagascar, and Nigeria. The variety of geological settings contributes to the wide range of colors found in spinel.
Gemological Properties
Spinel is a magnesium aluminum oxide with the chemical formula MgAl₂O₄. It crystallizes in the isometric system, forming octahedra. Its key gemological properties include:
| Property | Value |
|---|---|
| Chemical Formula | MgAl₂O₄ |
| Crystal System | Isometric |
| Hardness (Mohs) | 8 |
| Refractive Index | 1.712 – 1.762 |
| Specific Gravity | 3.58 – 4.00 |
| Cleavage | None |
| Fracture | Conchoidal |
Spinel’s hardness of 8 on the Mohs scale makes it a durable gemstone suitable for everyday wear. Its single refractive index and lack of cleavage contribute to its brilliance and resistance to chipping. The specific gravity varies depending on the chemical composition of the spinel, with iron-rich spinels being denser.
Spinel exhibits a wide range of colors, including red, pink, blue, purple, green, yellow, and black. Red spinel is particularly prized, often rivaling the color of ruby. Blue spinel, caused by trace amounts of iron and cobalt, is also highly sought after. Spinel can also display the asterism phenomenon, forming star-shaped patterns when cut as a cabochon.
Symbolism and Metaphysical Beliefs
While specific historical symbolism directly linked to spinel is limited due to its past misidentification as ruby, modern interpretations attribute various meanings to the gem. Spinel is often associated with revitalization, renewal, and overcoming challenges. It is believed to inspire passion, courage, and creativity.
Some modern sources suggest that spinel can help to calm the mind, release negativity, and promote physical healing. However, these metaphysical beliefs are not widely accepted within formal gemology and are considered more aligned with New Age practices. The association with August, and therefore with those born in that month, links spinel to qualities of strength, leadership, and practicality.
Care and Cleaning
Due to its hardness of 8 on the Mohs scale, spinel is a relatively durable gemstone. However, like all jewelry, it requires proper care to maintain its brilliance. Spinel can be safely cleaned using warm, soapy water and a soft brush. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaners, as these can potentially damage the stone.
It is advisable to remove spinel jewelry before engaging in strenuous activities or when exposed to harsh chemicals. Regular cleaning will help to remove dirt and oils, allowing the gem to sparkle and retain its beauty. Spinel’s excellent toughness makes it suitable for all types of jewelry, including rings, earrings, pendants, and bracelets.
Conclusion
Spinel’s journey from being mistaken for ruby to achieving recognition as a distinct and desirable gemstone, and ultimately as a modern birthstone for August in 2016, is a testament to its inherent beauty and enduring appeal. Its vibrant colors, excellent durability, and fascinating history make it a captivating choice for jewelry enthusiasts and collectors alike. As awareness of spinel grows, its popularity is expected to continue to rise, solidifying its place among the world’s most cherished gemstones.