October is unique among the months, possessing not one, but two recognized birthstones: opal and tourmaline. Both gemstones offer a dazzling array of colors and possess a rich history steeped in lore and symbolism. While opal historically held the sole designation, tourmaline was officially added as an alternative in 1912 by the National Association of Jewellers, now known as Jewellers of America. This article will explore the origins, properties, cultural significance, and modern appreciation of these captivating October birthstones.
History and Lore
The story of October’s birthstones is interwoven with ancient beliefs and evolving traditions. The origins of the word “opal” remain somewhat debated, with potential roots in the Latin opalus, and connections to the Ancient Greek opallios, meaning “to see a change in color,” and the Sanskrit upala, meaning “precious stone.” Romans referred to opals as cupid paederos, or “child as beautiful as love,” highlighting the gem’s association with affection and beauty.
Tourmaline’s name originates from the Sinhalese word toramalli, meaning “stone with mixed colors,” a fitting description given the gem’s remarkable pleochroism and diverse color range. While Dutch traders are often credited with discovering tourmaline in the late 17th or early 18th century off the coast of Italy, the gem was known and utilized for centuries prior. In the 1500s, Spanish conquistadors encountered green tourmaline in Brazil, initially mistaking it for emerald. It wasn’t until the 1800s that mineralogists formally recognized tourmaline as a distinct mineral species.
The formalized association of birthstones with specific months began in 1870 with a pamphlet published by Tiffany & Co., which initially designated opal as October’s birthstone. The standardization of birthstone lists continued with the National Association of Jewellers in 1912, solidifying opal’s primary position and adding tourmaline as a recognized alternative.
Geological Formation and Sources
Opal is unique in that it is not a true crystal but a mineraloid – an amorphous form of hydrated silica. It forms through the gradual natural heating of silica gel found in cracks and voids within rocks. The play-of-color, opal’s most defining characteristic, is a result of the diffraction of light by microscopic silica spheres within its structure.
The most significant source of opal is Australia, particularly the regions of Lightning Ridge, known for its prized black opal; White Cliffs, New South Wales, for white opal; and Mintabie, Andamooka, and Coober Pedy in South Australia. Boulder opal is exclusively found in Queensland. Other opal deposits are found in Ethiopia, Mexico, Brazil, Central Europe, Honduras, Indonesia, Madagascar, Peru, Turkey, and the United States. The harsh climate of Lightning Ridge, Australia, necessitates that miners often live underground to escape the intense heat.
Tourmaline forms in igneous and metamorphic rocks, often alongside quartz and feldspar. Its diverse chemical composition allows for a wide range of colors and varieties. Mining locations for tourmaline are varied, with significant deposits found in Brazil, where it was first mistaken for emerald, as well as in other locations around the globe.
Gemological Properties
Both opal and tourmaline exhibit distinct gemological properties. Opal’s defining characteristic is its play-of-color, which varies in pattern and intensity. It has a hardness of 5.5-6.5 on the Mohs scale. Opal is categorized into two main varieties: precious opal, which displays play-of-color, and common opal, which does not.
Tourmaline, on the other hand, is a complex borosilicate mineral with a hardness ranging from 7 to 7.5 on the Mohs scale, making it more durable than opal. Its chemical composition varies, resulting in a wide spectrum of colors. Some notable varieties include:
- Rubellite: Red to pink tourmaline
- Chrome Tourmaline: Emerald green tourmaline
- Paraíba Tourmaline: Neon green to blue-to-violet tourmaline
The vast range of colors in tourmaline is attributed to trace elements within its crystal structure. The name “tourmaline” itself reflects this characteristic, derived from the Sinhalese word meaning “stone with mixed colors.”
Here's a table summarizing key gemological properties:
| Property | Opal | Tourmaline |
|---|---|---|
| Chemical Formula | Hydrated Silica | Complex Borosilicate |
| Hardness (Mohs) | 5.5 - 6.5 | 7 - 7.5 |
| Play-of-Color | Present (Precious) | Absent |
| Luster | Vitreous | Vitreous |
| Transparency | Translucent to Opaque | Transparent to Opaque |
Symbolism and Metaphysical Beliefs
Throughout history, both opal and tourmaline have been attributed with various symbolic meanings and metaphysical properties. Ancient Romans believed opals symbolized purity, hope, and perspective. However, a superstition arose in the 1800s claiming opals were cursed, though this belief was not widely held in ancient societies, with many cultures, particularly in China, considering them lucky.
Opal is believed to possess healing properties related to vision and the mind, potentially treating eyesight problems, boosting cognitive abilities, and even offering glimpses into the future.
Tourmaline, often called the “Stone of Reconciliation,” symbolizes compassion, open-mindedness, and forgiveness. Different colors of tourmaline are thought to have specific healing properties. Black tourmaline is believed to provide protection and enhance self-confidence, while pink tourmaline is associated with love, energy, and smoothing relationship troubles. Green tourmaline is said to promote courage, strength, and stamina. Tourmaline is also considered an excellent tool for balancing the chakras and understanding oneself and others.
Care and Cleaning
Due to its lower hardness, opal requires careful handling and cleaning. It is susceptible to scratching and should be protected from impacts. Cleaning opal involves using a soft cloth and lukewarm soapy water. Avoid harsh chemicals or ultrasonic cleaners.
Tourmaline, with its greater hardness, is more durable and can withstand more rigorous cleaning. It can be cleaned with warm soapy water, a soft brush, and rinsed thoroughly. Ultrasonic cleaners are generally safe for tourmaline, but caution should be exercised with stones that have been fracture-filled.
Conclusion
Opal and tourmaline, the captivating birthstones of October, represent a fascinating blend of history, geological wonder, and symbolic meaning. From ancient beliefs in their healing powers to their modern appreciation for their beauty and versatility, these gemstones continue to enchant and inspire. Whether admired for their vibrant play-of-color or their diverse range of hues, opal and tourmaline offer a unique and meaningful connection to the month of October.