October is uniquely blessed with not one, but two recognized birthstones: opal and tourmaline. Both gemstones offer a stunning array of colors and captivating histories, making them cherished symbols of the tenth month. While opal holds the distinction as the traditional October birthstone, tourmaline was added in 1952 to provide a wider selection and address perceptions of opal’s durability. This article will explore the origins, properties, lore, and significance of both these remarkable gems.
History and Lore
The story of opal begins in ancient times. The name “opal” is believed to originate from the Sanskrit word upala, meaning “precious stone,” adopted into the Roman opalus. Ancient Greeks associated opal with the gift of prophecy and protection from disease. Europeans long considered it a symbol of purity, hope, and truth, believing it embodied the virtues of all colored stones. Bedouin tribes held the belief that opal contained lightning and fell to earth during thunderstorms.
Tourmaline’s history is equally rich, though its identification as a distinct gem is more recent. The Sinhalese word toramalli, meaning “stone with mixed colors,” describes the gem’s remarkable polychromism. For centuries, tourmaline was often mistaken for other gemstones, such as ruby and emerald. A notable example is the “Caesar’s Ruby” in the Russian crown jewels, which is, in fact, a red tourmaline (rubellite). Green tourmaline crystals discovered in Brazil during the 1500s were initially believed to be emeralds. It wasn’t until the 19th century that tourmaline was formally recognized as a unique mineral species. The last empress of the Chi’ing Dynasty in China was a passionate collector of tourmaline, particularly vivid pink and magenta varieties, and was even buried with a tourmaline pillow.
Geological Formation and Sources
Opal is a mineraloid – meaning it lacks a crystalline structure – formed by the gradual natural heating of silica gel found in cracks within rocks. The resulting stone displays a unique “play-of-color,” a shifting kaleidoscope of rainbow hues. While once considered relatively rare, the discovery of rich opal mines in Australia significantly increased its availability.
Tourmaline, conversely, is a crystalline borosilicate mineral. Its diverse colors stem from trace elements within its chemical composition. The most prized variety, Paraíba tourmaline, originates from Brazil and exhibits intense shades of violet-blue and blue-green due to its copper content. Tourmaline can also be found in a variety of other locations, displaying colors ranging from vivid greens and pinks to electric blues and blacks. Some tourmaline varieties, like Watermelon Tourmaline, showcase both pink and green hues within a single crystal.
Gemological Properties
Both opal and tourmaline exhibit a wide range of properties, contributing to their individual appeal. Opal is valued for its play-of-color, a phenomenon caused by the diffraction of light within its microscopic structure. This effect is most prominent in precious opal, while common opal lacks this characteristic.
Tourmaline’s properties vary depending on the specific variety. It can be piezoelectric, meaning it generates an electrical charge when pressure is applied – a property utilized in pressure gauges for submarines. The gem’s hardness also varies, but generally falls within a range suitable for jewelry.
Here's a comparative overview of key properties:
| Property | Opal | Tourmaline |
|---|---|---|
| Chemical Formula | Hydrated amorphous silica (SiO₂·nH₂O) | Complex borosilicate (XY₃Z₆(BO₃)₃Si₆O₁₈(OH,F)₄) |
| Hardness (Mohs) | 5.5 - 6.5 | 7 - 7.5 |
| Specific Gravity | 1.98 - 2.50 | 3.06 - 3.98 |
| Crystal System | Amorphous | Trigonal |
| Key Feature | Play-of-color | Wide range of colors, piezoelectricity |
Symbolism and Metaphysical Beliefs
Throughout history, both opal and tourmaline have been imbued with symbolic meaning. Opal is often associated with confidence, hope, and faithfulness. Ancient cultures believed it possessed protective qualities and the ability to bestow prophetic visions.
Tourmaline’s symbolism is tied to its diverse colors. Pink tourmaline is believed to embody love, compassion, and gentleness, while black tourmaline is thought to protect against negativity and enhance self-confidence. Green tourmaline is associated with courage, strength, and stamina. Overall, tourmalines are believed to increase understanding and empathy.
Care and Cleaning
Due to its relatively lower hardness, opal requires careful handling. It is susceptible to scratching and can be damaged by harsh chemicals or sudden temperature changes. Cleaning opal jewelry should be done with a soft cloth and mild soapy water. Avoid ultrasonic cleaners and harsh abrasives.
Tourmaline, being harder than opal, is more durable and can withstand more rigorous cleaning. However, it is still advisable to avoid harsh chemicals and ultrasonic cleaners. A soft brush and mild soapy water are sufficient for routine cleaning.
October’s Dual Legacy
The selection of both opal and tourmaline as October birthstones reflects a desire to offer a wider range of choices to those born in this month. In 1952, the National Association of Jewelers added tourmaline to the list, partly due to perceptions that opal was too feminine or lacked sufficient durability. This decision acknowledged the evolving preferences of jewelry buyers and the increasing availability of diverse gemstones. Today, both opal and tourmaline continue to be celebrated for their beauty, history, and symbolic significance, offering a captivating duality for those born in October.
Conclusion
Opal and tourmaline represent a fascinating pairing as October’s birthstones. From the ancient lore surrounding opal’s origins to the centuries of misidentification that shrouded tourmaline’s true nature, both gems possess a rich and compelling history. Their diverse colors, unique properties, and symbolic meanings make them treasured additions to any gemstone collection and meaningful gifts for those celebrating birthdays in the tenth month.