October boasts not one, but two recognized birthstones: the captivating opal and the richly colored tourmaline. Both gemstones are prized for their aesthetic beauty and carry unique symbolism, offering a diverse range of choices for those born in the tenth month of the year. This article provides a comprehensive overview of these October birthstones, exploring their history, geological origins, gemological properties, and cultural significance.
History and Lore
For a long period, opal was the sole birthstone associated with October. Historical records indicate a long-standing connection between the gem and the month, though the precise origins of this association are not detailed in the available sources. More recently, tourmaline was added as a secondary birthstone, likely due to its wide spectrum of colors and increasing popularity. The addition of tourmaline provides jewelry lovers with a broader selection, reflecting the autumnal hues of October. The decision to include both stones acknowledges opal’s traditional link while embracing tourmaline’s diverse appeal.
The name “tourmaline” itself is derived from the Sinhalese word “tura mali,” meaning “stone of many colors,” hinting at the gem’s remarkable chromatic variety. This diversity has contributed to its appeal throughout history.
Geological Formation and Sources
Tourmaline is found in a variety of geological settings, with significant deposits in Brazil, Sri Lanka, Tanzania, Madagascar, and even the United States. Its formation often occurs in granite pegmatites, metamorphic rocks, and alluvial deposits. The gem’s chemical composition is complex, leading to a wide range of colors and varieties.
Opal, conversely, is known for its unique formation process. A significant source of high-quality opal is Coober Pedy, South Australia, where the “Virgin Rainbow,” a 72-carat opal valued at over $1 million, was unearthed in 2003. Opal forms from silica-rich solutions that seep into cracks and voids in the earth, eventually solidifying into the gemstone.
Gemological Properties
Tourmaline exhibits a hardness of 7 to 7.5 on the Mohs scale, making it relatively durable and suitable for everyday wear. It is commonly cut into cabochons, though faceted cuts are also prevalent. The gem’s chemical composition is complex, belonging to the cyclosilicate group of minerals. Its wide range of colors – including pink, green, red, blue, and yellow – is a defining characteristic. Bi-color and tri-color tourmalines, such as watermelon tourmaline displaying red, green, and white hues, are particularly intriguing. Darker tones of tourmaline, however, can absorb significant light, sometimes appearing almost black.
Opal, with a Mohs hardness of 5-6.5, is considerably softer than tourmaline and therefore more susceptible to scratches and damage. This fragility makes it better suited for jewelry pieces that won’t encounter frequent abrasion, such as necklaces or earrings. Opal is unique for its “play of color,” a mesmerizing display of iridescent flashes caused by the diffraction of light within its internal structure.
The following table summarizes key gemological properties:
| Property | Tourmaline | Opal |
|---|---|---|
| Mohs Hardness | 7-7.5 | 5-6.5 |
| Toughness | Fair | N/A |
| Chemical Group | Cyclosilicate | Hydrated Silica |
| Common Colors | Pink, Green, Blue | Iridescent |
| Typical Cut | Cabochon, Faceted | Cabochon |
Symbolism and Metaphysical Beliefs
Both tourmaline and opal are imbued with symbolic meaning. Tourmaline is believed to represent love, prosperity, and harmony, making it a meaningful gift for expressing affection and goodwill. Opal, on the other hand, is associated with luck, hope, and spiritual awakening. These differing symbolic associations allow individuals to choose the stone that best resonates with their intentions or the message they wish to convey.
Care and Cleaning
Due to its greater hardness, tourmaline is more resistant to wear and tear than opal. However, both gemstones require careful handling. Tourmaline is generally stable to light and unaffected by most chemicals, but exposure to high heat can alter its color, and sudden temperature changes can cause fracturing. Therefore, warm, soapy water is recommended for cleaning tourmaline. Ultrasonic and steam cleaners are not advised.
Opal’s lower hardness necessitates even more gentle care. It should be protected from scratches and impacts. Cleaning opal jewelry with warm, soapy water is also recommended, avoiding harsh chemicals or abrasive materials.
Market Value and Rarity
The value of both tourmaline and opal can vary significantly depending on quality, size, and rarity. High-quality, large-carat specimens of both gemstones command premium prices. The rarest variety of opal, Australian black opal, can be worth $10,000 to $50,000 per carat. Similarly, Paraiba tourmaline, known for its vibrant neon blue-green color, can range from $2,000 to $5,000 per carat.
According to available data, the most expensive birthstones, in order of value, are diamond, ruby, emerald, sapphire, alexandrite, aquamarine, peridot, garnet, blue topaz, tourmaline, amethyst, and citrine. Tourmaline falls within the $100-$400 per carat range for common varieties, while rarer types can be significantly more expensive. Citrine is the least expensive, valued at $10-$50 per carat.
The three rarest birthstones are diamond, ruby, and emerald, followed by alexandrite and tanzanite. While tourmaline and opal are not among the absolute rarest, certain varieties, like Paraiba tourmaline and Australian black opal, are highly sought after and command substantial prices.
Based on Google Trends data, opal currently has a higher search volume than tourmaline, suggesting it is the more popular choice for October birthstones.
Choosing Between Tourmaline and Opal
When selecting an October birthstone, several factors should be considered. If the jewelry will be worn daily, tourmaline’s greater durability makes it a more practical choice. If the intention is to convey specific emotions or spiritual power, tourmaline is well-suited for expressing love and inner peace, while opal is associated with luck and spiritual awakening. Budget is also a key consideration. While common varieties of both stones are relatively affordable, top-quality specimens, particularly Australian black opal, can be significantly more expensive.
Ultimately, the best choice depends on personal preference and the desired aesthetic. Both tourmaline and opal offer unique beauty and symbolism, making October a particularly exciting month for birthstone enthusiasts.
Conclusion
Tourmaline and opal, the captivating birthstones of October, represent a harmonious blend of color, history, and symbolism. Tourmaline’s durability and diverse hues, coupled with opal’s mesmerizing play of color and association with good fortune, provide a wealth of options for those seeking a meaningful and beautiful gemstone. Whether chosen for their aesthetic appeal, symbolic significance, or geological origins, these October birthstones continue to enchant and inspire.