October possesses a unique distinction among the birthstone months: it is represented by not one, but two captivating gemstones – opal and tourmaline. While opal historically held sole claim to the month, the early 20th century saw tourmaline rise to co-headliner status, offering October-born individuals a choice between a stone celebrated for its shifting internal fire and another renowned for its diverse and saturated colors. This article delves into the history, geological origins, gemological properties, and cultural significance of both opal and tourmaline, exploring their individual characteristics and shared role as symbols of October.
History and Lore
The story of October’s birthstones is one of evolving tradition. For centuries, opal reigned as the sole representative of the month. Ancient Greeks believed opals were formed from the tears of joy shed by Zeus after defeating the Titans, attributing to the gem a divine origin and a connection to happiness. Indigenous Australian lore also features prominently in opal’s history, with myths describing the stone’s creation through the Rainbow Serpent’s iridescent scales falling to earth or emerging from the touch of ancestral Creator spirits traveling by rainbow. These stories highlight the gem’s association with color, light, and the natural world.
The formalized designation of birthstones began to take shape in the 19th and early 20th centuries. Tiffany & Co. published “Gregorian Birthstone Poems” in 1870, featuring opal as October’s stone. However, it was the National Association of Jewelers (now Jewellers of America) in 1912 that officially recognized tourmaline as an alternative to opal. This decision stemmed from a desire to provide options for months with birthstones that were either rare or subject to misunderstanding. In 1950, the Jewellery Industry Council of America further refined this by specifically naming pink tourmaline as the October alternative. More recent lists, such as the 2016 American list, grant equal priority to both opal and pink tourmaline, while the 2013 UK list retains opal as the sole October birthstone.
The historical context of October itself adds another layer of meaning. Rooted in the Latin “octo” for eight, and known as “Winterfylleth” (winter full moon) by the Anglo-Saxons, the month symbolizes transition and the cyclical nature of life. Ancient Roman celebrations like Mundus Patet, where the realms of the living and dead were believed to open, further contribute to October’s association with themes of fulfillment and the life cycle – themes that resonate with the unique qualities of both opal and tourmaline.
Geological Formation and Sources
Both opal and tourmaline form under distinct geological conditions. Opal is a hydrated amorphous form of silica, meaning it lacks a crystalline structure. It typically forms in sedimentary environments where silica-rich water percolates into cracks and voids in rocks. As the water evaporates, it leaves behind deposits of silica, which gradually build up to form opal. Australia is the world’s primary source of opal, producing the vast majority of precious opal, known for its play-of-color.
Tourmaline, in contrast, is a crystalline borosilicate mineral. It forms in igneous and metamorphic rocks, often in pegmatites – coarse-grained igneous rocks. The diverse chemical composition of tourmaline leads to a wide range of colors and varieties. Maine, in the United States, is particularly renowned for its tourmaline deposits, found in the western mountains. These local gems hold a special significance for jewelers and collectors in the region, supporting local mining communities and representing the natural beauty of the state. While Maine is a notable source, tourmaline is also found in Brazil, Africa, and Afghanistan, among other locations.
Gemological Properties
Opal is characterized by its unique “play-of-color,” a phenomenon caused by the diffraction of light within its internal structure. This creates flashes of rainbow hues that shift and change as the stone is viewed from different angles. Opal’s hardness ranges from 5.5 to 6.5 on the Mohs scale, making it relatively soft and susceptible to scratching.
Tourmaline, on the other hand, exhibits a wider range of properties depending on its specific variety. It generally has a hardness of 7 to 7.5 on the Mohs scale, making it more durable than opal. The chemical formula of tourmaline is complex, varying based on its composition, but it generally includes boron, silicon, aluminum, and other elements. Pink tourmaline, the designated alternative October birthstone, is particularly valued for its vibrant color and association with love and compassion.
The following table summarizes key gemological properties:
| Property | Opal | Tourmaline |
|---|---|---|
| Chemical Formula | SiO₂·nH₂O | Complex Borosilicate |
| Hardness (Mohs) | 5.5 - 6.5 | 7 - 7.5 |
| Crystal System | Amorphous | Trigonal |
| Key Feature | Play-of-Color | Diverse Colors |
Symbolism and Metaphysical Beliefs
Throughout history, both opal and tourmaline have been attributed with various symbolic meanings and metaphysical properties. Opal has been associated with hope, purity, and truth. However, it has also been subject to superstition, with some believing it brought bad luck to those not born in October.
Tourmaline, particularly pink tourmaline, is often linked to love, friendship, compassion, and emotional healing. It is believed to encourage positive energy and smooth relationship troubles. Different colors of tourmaline are also associated with specific properties; for example, green tourmaline is thought to promote growth and vitality. Rose quartz, another alternative suggested for October, is strongly associated with love and self-forgiveness. Beryl is also listed as an alternative, though its connection to October is less prominent.
Care and Cleaning
Due to its relatively low 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, being more durable, can withstand more rigorous cleaning. It can be cleaned with warm soapy water and a soft brush. Ultrasonic cleaners are generally safe for tourmaline, but caution should be exercised with stones that have been treated or contain fractures.
Conclusion
Opal and tourmaline, the dual birthstones of October, represent a fascinating blend of history, geology, and symbolism. From ancient myths to modern gemological understanding, these stones have captivated cultures for centuries. While opal historically held sole claim to the month, the inclusion of tourmaline as an alternative reflects a growing appreciation for the diversity and beauty of the gemstone world. Whether one chooses the shifting fire of opal or the saturated colors of tourmaline, both stones offer a meaningful connection to the unique spirit of October.