October is unique among the months, possessing not one, but two recognized birthstones: opal and tourmaline. This tradition, formalized in the late 19th and early 20th centuries, reflects both historical precedent and a desire to offer a wider selection of gemstones to suit diverse preferences. Both opal and tourmaline boast a rich history, captivating beauty, and a range of optical phenomena that have fascinated cultures for centuries. This article will explore the origins, properties, symbolism, and modern appreciation of these October birthstones.
History and Lore
The story of October’s birthstones begins with opal. Its history stretches back to ancient times, with origins traced to India, where it was known as Upala, meaning “precious stone.” The Romans referred to it as opalus. Ancient Greeks believed opal bestowed the power of prophecy and protected its wearer from disease. In Europe, opal became associated with purity, hope, and truth, and was once believed to contain the virtues of all colored stones. The Bedouins held the belief that opal contained lightning and originated from the sky during thunderstorms. Notably, opal was a favored gem in wedding anniversary celebrations, specifically for the 14th year of marriage.
Tourmaline’s history, while also ancient, gained prominence more recently. Pink tourmaline, specifically, experienced a surge in popularity in the late 1800s due to the patronage of the Chinese Empress Dowager Tzu-Hsi. She developed a deep affection for the gemstone, acquiring nearly the entire output from California mines. Even in death, her devotion continued, as she was buried with a pink tourmaline pillow, and the remainder of her collection was crafted into intricate carvings.
The formalized designation of birthstones is a relatively modern concept. Prior to the 19th century, associations between months and gemstones were less standardized. The publication of “Gregorian Birthstone Poems” by Tiffany & Co. in 1870 marked an early attempt to codify these associations, initially listing opal as October’s sole birthstone. The National Association of Jewellers (now Jewellers of America) further refined the list in 1912, officially recognizing opal as the primary October birthstone and tourmaline as an alternative.
Geological Formation and Sources
Opal is unique among gemstones for its formation process. It is not a crystalline mineral like many others, but rather a hydrated amorphous form of silica. This means it lacks a regular atomic structure and contains a significant amount of water within its composition. Opal forms in cracks and voids within rocks, where silica-rich solutions seep in and deposit the silica over long periods.
Australia is the world’s primary source of opal, accounting for the vast majority of global production. Within Australia, significant deposits are found in South Australia (Coober Pedy, Mintabie, Andamooka) and Queensland (Boulder opal, found in a single location). White opal is mined in the White Cliffs area of New South Wales. More recently, Ethiopia has emerged as a significant opal source, with mines located near Wegel Tena in Wollo Province and in Shewa Province, yielding both common and coveted black opal varieties. Mexico, specifically the Querétaro state, is known for its fire opal, characterized by its yellow, orange, and reddish hues.
Pink tourmaline, a variety of the elbaite mineral group, forms in distinctive prism-like crystals with long hexagonal structures. These crystals develop in pegmatites, which are coarse-grained igneous rocks formed during the final stages of magma cooling. The diverse range of elements present during formation contributes to the wide spectrum of colors found in tourmaline. While pink tourmaline has been sourced from various locations, the historical connection to California mines, fueled by the Empress Dowager Tzu-Hsi’s demand, remains noteworthy.
Gemological Properties
Opal’s defining characteristic is its “play-of-color,” a mesmerizing display of shifting rainbow hues. This phenomenon is caused by the diffraction of light as it passes through microscopic spheres of silica within the gem. The size and arrangement of these spheres determine the colors observed. Opal’s hardness is relatively low, ranging from 5.5 to 6.5 on the Mohs scale, making it susceptible to scratches and requiring careful handling.
Pink tourmaline, on the other hand, exhibits a hardness of 7 to 7.5 on the Mohs scale, making it considerably more durable than opal. It forms in long, prismatic crystals and displays a variety of pink shades. Some tourmaline crystals even exhibit multiple colors, known as watermelon tourmaline, a highly sought-after variety. The color in pink tourmaline is attributed to the presence of manganese. Tourmaline’s chemical composition is complex, consisting primarily of elbaite, a sodium lithium aluminum borosilicate.
The following table summarizes key gemological properties:
| Property | Opal | Pink Tourmaline |
|---|---|---|
| Chemical Formula | SiO₂·nH₂O | (Na,Ca)(Al,Li,Mg)₃(Al,Fe,Mn)₆(BO₃)₃(Si₆O₁₈)(OH)₄ |
| Hardness (Mohs) | 5.5 - 6.5 | 7 - 7.5 |
| Crystal System | Amorphous | Trigonal |
| Specific Gravity | 1.98 - 2.15 | 3.07 - 3.20 |
| Key Characteristic | Play-of-Color | Diverse Pink Hues |
Symbolism and Metaphysical Beliefs
Throughout history, both opal and tourmaline have been imbued with symbolic meaning. As previously mentioned, opal was associated with purity, hope, and truth in Europe, and believed to possess protective and prophetic powers in ancient cultures.
Pink tourmaline, beyond its association with love and compassion due to its color, is believed to promote emotional healing and balance. It is often considered a stone of reassurance and positive energy. The Empress Dowager Tzu-Hsi’s fascination with pink tourmaline suggests a perceived connection to power, beauty, and longevity.
Care and Cleaning
Due to its lower hardness, opal requires careful handling and cleaning. It is susceptible to scratches and can be damaged by harsh chemicals or ultrasonic cleaners. Cleaning should be done with a soft cloth and mild soapy water. Avoid prolonged exposure to heat or direct sunlight, as this can cause the opal to lose its water content and crack.
Pink tourmaline, being more durable, 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 pink tourmaline, but caution should be exercised with stones that may have fractures or inclusions.
Conclusion
October’s birthstones, opal and pink tourmaline, represent a captivating blend of history, geological wonder, and symbolic meaning. Opal, with its ethereal play-of-color, evokes a sense of mystery and enchantment, while pink tourmaline embodies love, compassion, and emotional healing. The dual designation of these gemstones reflects a modern appreciation for variety and the enduring allure of these beautiful creations of nature. Whether chosen for their aesthetic appeal, historical significance, or perceived metaphysical properties, opal and pink tourmaline continue to hold a special place in the hearts of gemstone enthusiasts and those born under the October sky.