October boasts a unique distinction among the birthstones: two recognized gems – opal and tourmaline. While many months claim a single stone, October offers a choice, reflecting both historical tradition and modern preferences. This article explores the history, gemological properties, and symbolism of these captivating gemstones, drawing upon available information to provide a comprehensive overview for enthusiasts and students of gemology.
History and Lore
The history of October birthstones is marked by evolution. Originally, opal held sole claim to the month, a position it maintained for a considerable period. However, in 1952, the National Association of Jewellers in the United States added tourmaline to the list. This decision stemmed from a desire to provide more options, particularly more affordable alternatives to opal, which was sometimes perceived as too feminine or lacking in durability. The addition of tourmaline broadened the appeal and accessibility of October birthstones.
Opal’s history is rich and varied, with ancient Romans associating it with love and hope. Its name is believed to originate from the Sanskrit word “upala,” meaning precious stone. Throughout history, opal has been prized for its unique play of colour, often likened to volcanic eruptions, galaxies, or fireworks.
Tourmaline, while gaining prominence more recently as a birthstone, also has a history rooted in ancient cultures. The name “tourmaline” comes from the Sinhalese word “toramalli,” meaning “finger of colour,” a fitting description given the gem’s diverse range of hues.
Geological Formation and Sources
The formation of opal differs significantly from that of tourmaline. Opal is a hydrated amorphous form of silica, meaning it lacks a crystalline structure. It forms in cracks and voids in the earth, typically in sedimentary rocks, where silica-rich water percolates through. Australia is the world’s primary source of opal, earning it the title of Australia’s national gemstone.
Tourmaline, on the other hand, is a crystalline borosilicate mineral. It forms in igneous and metamorphic rocks, often in pegmatites – coarse-grained igneous rocks. Tourmaline is found in a variety of locations worldwide, with significant deposits in Brazil, Sri Lanka, Africa, and the United States. The diverse geological settings contribute to the wide spectrum of colours found in tourmaline.
Gemological Properties
Both opal and tourmaline exhibit distinct gemological properties. Opal is characterized by its play of colour, a phenomenon caused by the diffraction of light within its microscopic structure. This play of colour is what makes each opal unique and highly valued. Opal typically ranges from 5.5 to 6.5 on the Mohs hardness scale, making it relatively softer than many other gemstones.
Tourmaline, in contrast, is a harder gemstone, ranging from 7 to 7.5 on the Mohs scale. This greater hardness makes it more durable and suitable for everyday wear. Tourmaline is known for its strong pleochroism, meaning it exhibits different colours when viewed from different angles.
Here's a comparative table summarizing 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 |
| Play of Colour | Present | Absent |
| Pleochroism | Absent | Present |
| Transparency | Typically translucent | Transparent to opaque |
Colour Variations
The colour range of both opal and tourmaline is remarkably diverse. Opal is famous for its kaleidoscopic display of colours, including red, orange, yellow, green, blue, and violet. The base colour of opal can be white, black, or crystal, with the play of colour appearing as flashes within these backgrounds.
Tourmaline exhibits an even broader spectrum of colours. It can be found in shades of pink, red (rubellite), green (verdelite), blue (indicolite), and even colourless. Pink tourmaline is particularly associated with October’s birthstone, though other colours are also widely accepted. The presence of trace elements during formation dictates the specific colour of tourmaline.
Symbolism and Metaphysical Beliefs
Throughout history, both opal and tourmaline have been attributed with various symbolic meanings. Opal has been associated with love, hope, and purity. Some cultures believed it could enhance creativity and inspire imagination. However, it also faced periods of superstition, with some associating it with bad luck, a belief that contributed to the desire for an alternative October birthstone.
Tourmaline is believed to promote self-confidence, kindness, and compassion. Different colours of tourmaline are associated with different properties. For example, pink tourmaline is often linked to emotional healing and love, while green tourmaline is believed to foster growth and abundance.
Care and Cleaning
Due to its relative softness, opal requires careful handling and cleaning. It is susceptible to scratches and should be protected from impacts. Cleaning opal involves using a soft cloth and lukewarm soapy water. Avoid harsh chemicals or ultrasonic cleaners, as these can damage the stone.
Tourmaline, being harder and more durable, is easier to care for. 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 enhanced.
October’s Astrological Connections
Individuals born in October fall under two zodiac signs: Libra (September 23 – October 22) and Scorpio (October 23 – November 21). The colours associated with Libra are pink and blue, aligning well with the pink tourmaline often chosen as an October birthstone. These pastel hues are said to soften one’s presence and open the heart. Scorpios, on the other hand, are associated with passion, loyalty, and bravery.
Conclusion
October’s birthstones, opal and tourmaline, represent a captivating blend of history, beauty, and symbolism. While opal has a long-standing tradition as the month’s gemstone, the addition of tourmaline has provided a wider range of choices and colours for those born in October. Both gems offer unique qualities and appeal to a diverse range of tastes, making October a truly special month for gemstone enthusiasts. The dual heritage of these stones reflects the evolving nature of birthstone traditions and the enduring allure of these precious gems.