October boasts a unique distinction among the birthstones: it is represented by not one, but two captivating gemstones – opal and tourmaline. Both gems are celebrated for their remarkable range of colors and rich histories, offering a diverse palette of options for those born in the tenth month of the year. This article will delve into the geological origins, historical significance, gemological properties, and symbolic meanings associated with both opal and tourmaline, providing a comprehensive overview of these October birthstones.
History and Lore
Opal has a long and storied past, prized for its captivating play of color. The Romans referred to it as “opalus,” a symbol of hope and purity, and frequently gifted it to those born in October, particularly diplomats. In medieval Europe, the gem was known as “ophthalmios,” or “eye-stone,” due to the belief that it could sharpen vision. By the 19th century, Queen Victoria’s fondness for Australian opals significantly boosted the gem’s popularity, cementing its association with October weddings and the autumn season. The name “opal” itself originates from the Sanskrit word “upala,” meaning “precious stone,” and the Greek “opallios,” meaning “to see a change of color.”
Tourmaline’s history, while also extensive, is somewhat different. The name derives from the Sinhalese word “tōramalli,” meaning “mixed colors,” a fitting descriptor for a gem renowned for its diverse hues. Historically, tourmaline was valued for its piezoelectric properties – its ability to become electrically charged when pressure is applied – and was even utilized in pressure gauges for submarines. The last empress of the Chi’ing Dynasty in China was a devoted collector of tourmaline, particularly vivid pink and magenta varieties, and was buried with a tourmaline pillow, demonstrating the gem’s high esteem in ancient cultures.
Geological Formation and Sources
Opal is a unique gem, composed of hydrated silica (SiO₂·nH₂O). It forms when silica-rich water seeps into crevices and voids within the Earth, gradually solidifying over millennia. This process can also occur within fossilized remains, resulting in “opalized fossils” or “opalized wood.” The majority of the world’s opal is sourced from Australia, specifically Lightning Ridge and Coober Pedy, known for their black opal. Significant deposits are also found in Ethiopia (Welo) and Mexico (Querétaro fire opal), while white opal is mined in Brazil. Crystal opal, with its almost transparent background, is found in the USA, specifically Nevada, Idaho, and Oregon. Fire opal, characterized by its yellow to red hues, is also sourced from Mexico, Brazil, and Oregon. Interestingly, NASA’s Curiosity rover has even discovered opal deposits on Mars.
Tourmaline, in contrast, is not a single mineral but a group of closely related minerals with a complex chemical composition. It forms in igneous and metamorphic rocks, often in pegmatites. Tourmaline exhibits an extraordinary range of colors, and the source locations vary depending on the specific variety. Vivid pink to red tourmaline, known as Rubellite, is particularly prized. Paraíba tourmaline, a rare copper-bearing gem from Brazil, is renowned for its intense violet-blue and blue-green shades. Tourmaline is found globally, with significant deposits in Brazil, Africa, and the United States.
Gemological Properties
Opal
- Composition: Hydrated silica (SiO₂·nH₂O)
- Mohs Hardness: 5.5 – 6.5
- Play of Color: Displays iridescence, reflecting a rainbow of colors.
- Types: White, Black, Fire, Boulder, and Crystal Opal. Common opal also exists without a play of color, appearing in uniform colors like pink, blue, and green.
Opal’s defining characteristic is its “play of color,” a mesmerizing display of iridescent hues caused by the diffraction of light within its internal structure. The base color of the opal – whether white, black, fire, boulder, or crystal – influences the overall appearance and value of the gem.
Tourmaline
Tourmaline’s properties vary depending on the specific species and color. However, some general characteristics include:
- Composition: Complex borosilicate mineral group.
- Color: Displays every color of the rainbow, including pink, red, green, blue, and black.
- Piezoelectricity: Some varieties exhibit piezoelectricity.
- Varieties: Rubellite (red), Indicolite (blue), Verdelite (green), Schorl (black), Watermelon Tourmaline (pink and green).
Tourmaline’s diverse color range is due to the presence of various trace elements within its crystal structure. The most sought-after colors include vivid pinks, electric blues, and the rare Paraíba tourmaline, known for its intense blue-green hues.
Symbolism and Metaphysical Beliefs
Opal is often associated with imagination, fidelity, creativity, innocence, and hope. It is believed to amplify emotions, allowing hidden feelings to surface and heal. Artists are said to wear opal to unlock imagination and spontaneous insight. In Greek legend, opal bestows the gift of prophecy. In Europe, opal and the color white symbolize purity and hope, making it a traditional gift for 14th wedding anniversaries.
Tourmaline carries a range of symbolic meanings depending on its color. Pink tourmaline is linked to love, compassion, and femininity, promoting self-love and emotional healing. Red tourmaline represents vitality, passion, and strength, instilling confidence and willpower. Green tourmaline inspires growth, balance, and renewal, fostering compassion and harmony. Tourmaline is also believed to increase understanding and empathy, warding off negative energy and emotion.
Care and Cleaning
Due to its relatively lower hardness (5.5-6.5 on the Mohs scale), opal is susceptible to scratches and requires careful handling. It should be stored separately from harder gemstones to prevent damage. Cleaning opal involves gentle washing with mild soap and warm water, avoiding harsh chemicals or ultrasonic cleaners.
Tourmaline, with a hardness of 7-7.5 on the Mohs scale, is more durable than opal. 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 fracture-filled.
October Zodiac Birthstones
Individuals born under the sign of Libra (September 24 – October 23) have opal, peridot, and lapis lazuli as their associated birthstones. Those born under Scorpio (October 24 – November 22) are linked to aquamarine, coral, and topaz.
Conclusion
Opal and tourmaline represent the captivating diversity of October’s birthstones. Opal, with its mesmerizing play of color and rich history, embodies hope, creativity, and emotional healing. Tourmaline, with its extraordinary range of hues and symbolic meanings, offers a spectrum of possibilities for self-expression and well-being. Whether chosen for their aesthetic beauty, historical significance, or metaphysical properties, these two gemstones offer a unique and meaningful connection to the month of October.