For centuries, a gemstone now celebrated in its own right was often mistaken for its more illustrious counterparts. Spinel, a captivating mineral with a rich history and vibrant range of colors, has recently secured its place as a modern birthstone for August, alongside peridot. This recognition marks a turning point for a gem long overshadowed by ruby and sapphire, a story steeped in regal misidentifications and a growing appreciation for its unique qualities. This article will delve into the history, geological origins, gemological properties, and symbolism of spinel, exploring its journey from historical confusion to contemporary acclaim.
History and Lore
The story of spinel is inextricably linked to instances of mistaken identity. Until 1783, the gem was frequently misidentified as ruby or sapphire, particularly red and blue varieties. This confusion stemmed from the similarities in appearance and the lack of sophisticated gemological testing methods. Several iconic historical jewels, once believed to be rubies, were later revealed to be spinel. Catherine the Great’s Imperial Crown of Russia, commissioned in 1763, features a prominent spinel mistakenly believed to be a ruby. Similarly, the Black Prince’s Ruby, adorning the British Imperial State Crown since 1838, is, in fact, a large spinel. The 361-carat Timur Ruby, gifted to Queen Victoria in 1851, also falls into this category of historically misattributed spinels.
These errors weren’t due to negligence, but rather a reflection of the gemological understanding of the time. It wasn’t until the 18th century that spinel was formally recognized as a distinct mineral species. Even after its identification, spinel suffered a period of diminished reputation due to the development of synthetic spinel in the 19th century, which was primarily used as an imitation of more valuable gemstones. This association with imitations contributed to a negative public perception, further obscuring its inherent beauty and value.
However, in more recent times, spinel has experienced a resurgence in popularity. In 2016, the American Gem Trade Association (AGTA) and Jewelers of America (JA) jointly announced spinel as an official August birthstone, a decision that surprised many in the gem world, given the relative stability of the birthstone list over the preceding century. The modern birthstone list, established in 1912, had only been amended a few times, in 1952 and 2002, before this addition. This recognition signifies a growing appreciation for spinel’s unique characteristics and its rightful place among the world’s most treasured gemstones.
In Myanmar (formerly Burma), spinel crystals found in the Mogok region are particularly revered. These high-luster, perfectly formed octahedral crystals are known locally as “anyon nat thwe,” meaning “spinels that have been cut and polished by the spirits.” This name reflects the cultural significance and mystical associations attributed to the gem in this region.
Geological Formation and Sources
Spinel forms under specific geological conditions, typically in metamorphic rocks and alluvial deposits. It is created when impure limestone is subjected to extreme heat and pressure. Chemically, spinel is a magnesium aluminum oxide (MgAl₂O₄), but impurities within the crystal structure give rise to its diverse range of colors. Pure spinel is colorless, but the presence of elements like chromium, iron, and cobalt results in hues of red, pink, purple, blue, and even black.
The primary sources of spinel are located in several regions around the world. Myanmar (Burma) is historically renowned for producing exceptional spinel crystals, particularly those from the Mogok region. Other significant sources include Sri Lanka and Thailand. More recent discoveries have expanded spinel production to include Pakistan, Afghanistan, Tajikistan, Tanzania, Vietnam, and Russia. The diversity of locations contributes to the variety of spinel colors and qualities found in the market.
Gemological Properties
Spinel possesses a unique combination of gemological properties that distinguish it from ruby and sapphire. While visually similar, spinel has a lower Mohs hardness – typically 8 – compared to ruby and sapphire (both 9). This means spinel is slightly less resistant to scratching. A key differentiating factor is spinel’s octahedral crystal structure and single refraction, unlike the double refraction seen in ruby and sapphire.
Spinel exhibits a wide spectrum of colors, making it a versatile gemstone. Red and cobalt blue spinels are considered the most valuable due to their vivid hues and rarity. Other colors include bright orange, bright pink, lavender, black, gray, pale pink, yellow, and brown. The value of a spinel is determined by its color, clarity, and size, with stones exceeding five carats being particularly prized for their rarity.
Clarity plays a crucial role in spinel’s value. Spinels with minimal inclusions are more desirable, as inclusions can detract from the stone’s brilliance and transparency. Jewelers commonly cut spinel into various shapes, including round, oval, octagon, pear, and cushion cuts, to maximize its beauty and brilliance.
Here's a table summarizing key gemological properties:
| Property | Value |
|---|---|
| Chemical Formula | MgAl₂O₄ |
| Hardness (Mohs) | 8 |
| Crystal System | Octahedral |
| Refractive Index | Not specified in sources |
| Specific Gravity | Not specified in sources |
| Luster | Vitreous |
Symbolism and Metaphysical Beliefs
Throughout history, spinel has been associated with various symbolic meanings. While specific metaphysical beliefs are not extensively detailed in the provided sources, its historical use in talismans and signet rings suggests a belief in its protective qualities. Ancient Greeks and Romans engraved sardonyx (mentioned alongside spinel as an August birthstone) with images of heroes and gods, believing it granted courage and victory. While this specifically refers to sardonyx, the association of gemstones with power and protection likely extended to spinel as well, given its frequent misidentification as ruby, a stone historically linked to courage and passion.
In some cultures, spinel is associated with revitalization and hope. As a relatively recent addition to the birthstone list, its modern symbolism is still evolving, but it is increasingly seen as a stone of renewal and positive energy.
Care and Cleaning
Due to its hardness of 8 on the Mohs scale, spinel is a relatively durable gemstone suitable for everyday wear. However, like all gemstones, it requires proper care to maintain its brilliance. Spinel should be cleaned with warm, soapy water and a soft brush. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaners, as these can damage the stone. It is also advisable to store spinel jewelry separately from other gemstones to prevent scratching.
Conclusion
Spinel’s journey from historical misidentification to modern birthstone status is a testament to its inherent beauty and unique qualities. Once overshadowed by ruby and sapphire, spinel has emerged as a gem worthy of recognition in its own right. Its vibrant colors, durable nature, and fascinating history make it a captivating choice for jewelry enthusiasts and collectors alike. As an August birthstone, spinel offers a distinctive and meaningful alternative to peridot and sardonyx, representing renewal, hope, and a rich legacy of regal association.