Tourmaline occupies a unique position among gemstones, celebrated for its extraordinary range of colors and increasingly recognized as a significant birthstone for those born in October. While opal traditionally held this designation, pink tourmaline was proposed as an alternative in 1952, a suggestion that gained acceptance and broadened to encompass all colors of tourmaline as valid October birthstones. This versatility, coupled with its appealing hardness and intriguing properties, has cemented tourmaline’s popularity among gem enthusiasts and jewelry buyers alike. This article will explore the history, geological origins, gemological characteristics, and symbolism associated with this captivating gem.
History and Lore
The story of tourmaline is one of mistaken identity and eventual recognition. For centuries, tourmaline crystals were often confused with other gemstones due to their similar appearances. As early as the 1500s, Spanish conquistadors in Brazil misidentified green tourmaline as emerald. Similarly, red tourmaline was frequently mistaken for ruby, and blue varieties for sapphire. This confusion stemmed from a lack of sophisticated gemological testing methods and a reliance on color as the primary means of identification. The name “tourmaline” itself originates from the Sinhalese word toramalli, meaning “mixed stones,” a reflection of the gem’s frequent display of multiple colors within a single crystal, and the early practice of Dutch merchants collecting multicolored pebbles from Sri Lanka.
It wasn’t until the 19th century, with the development of advanced optical and physical testing techniques, that tourmaline was definitively recognized as a distinct mineral species. A particularly notable example of this historical misidentification is the “Caesar’s Ruby” in the Russian crown jewels, which is, in fact, a red tourmaline (rubellite). The gem’s ability to exhibit a wide spectrum of hues led ancient mystics to believe it could inspire artistic expression, offering a “color palette for every mood.”
Geological Formation and Sources
Tourmaline is not a single mineral but a group of closely related boron silicate minerals with varying chemical compositions. These differences in composition account for the gem’s remarkable color variations. Tourmaline typically forms in pegmatites – subterranean intrusions of magma – which are rich in rare elements. These geological environments provide the necessary ingredients for tourmaline crystallization.
Brazil is currently the most significant source of tourmaline, particularly from the state of Minas Gerais, where pegmatites have yielded a vast array of specimens over centuries. However, the discovery of copper-bearing tourmalines in the Paraíba State of Brazil in the late 1980s revolutionized the tourmaline market. These tourmalines, exhibiting electric green, blue, and violet hues, are highly prized for their vivid colors and rarity, commanding premium prices. Similar copper-bearing tourmalines have since been found in Mozambique and Nigeria.
Beyond Brazil, tourmaline is also mined in Afghanistan, Pakistan, Kenya, Madagascar, and Mozambique. Historically, the United States, specifically California and Maine, have been important producers of fine tourmaline, though production is sporadic.
Gemological Properties
Tourmaline’s appeal extends beyond its color. It boasts a hardness of 7 to 7.5 on the Mohs scale, making it durable enough for everyday wear in jewelry. This hardness means it is resistant to scratching from most common materials. The gem exhibits pyroelectricity – the ability to generate an electrical charge when heated – and piezoelectricity – the ability to generate a charge when subjected to pressure. When charged, tourmaline can even attract or repel dust particles.
The chemical composition of tourmaline is complex and varies depending on the specific variety. However, all tourmalines are boron silicate minerals. Different trace elements contribute to the diverse range of colors observed. For example, iron is responsible for the dark shades found in schorl, a black tourmaline variety that constitutes approximately 95% of all tourmaline mined, though much of it is not gem-quality. Copper is the key element responsible for the vibrant colors of Paraíba tourmaline.
Several tourmaline varieties are recognized based on their color, including:
- Rubellite: Pink, red, purplish-red, orangy-red, or brownish-red tourmaline.
- Indicolite: Dark violetish-blue, blue, or greenish-blue tourmaline.
- Chrome Tourmaline: Emerald green tourmaline, colored by chromium.
- Paraíba Tourmaline: Neon green to blue-to-violet tourmaline, colored by copper.
- Schorl: Black tourmaline, rich in iron.
Tourmaline’s pleochroism – the display of different colors when viewed from different angles – is another notable characteristic.
The following table summarizes key gemological properties:
| Property | Value |
|---|---|
| Hardness (Mohs) | 7 – 7.5 |
| Chemical Formula | Complex Boron Silicate |
| Luster | Vitreous |
| Crystal System | Trigonal |
| Cleavage | Imperfect |
| Specific Gravity | 3.06 – 3.10 |
Symbolism and Metaphysical Beliefs
Throughout history, tourmaline has been attributed with various symbolic meanings and metaphysical properties. Ancient mystics believed the gem could inspire artistic expression due to its diverse color palette. More broadly, tourmaline is often associated with protection, grounding, and emotional healing. Different colors of tourmaline are believed to possess specific energies. For example, pink tourmaline is often linked to love and compassion, while black tourmaline is thought to offer protection against negative energies. While these beliefs are not scientifically substantiated, they contribute to the gem’s enduring appeal.
Care and Cleaning
Tourmaline is generally suitable for everyday wear due to its hardness. However, it is advisable to avoid exposing tourmaline to harsh chemicals or extreme heat. The gem is best cleaned with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are not recommended, as they may damage the stone. Prolonged exposure to water should also be avoided, particularly for tourmaline doublets or triplets, as it can weaken the adhesive.
Conclusion
Tourmaline stands as a testament to the beauty and complexity of the natural world. From its captivating array of colors to its intriguing geological origins and historical journey, this October birthstone offers a wealth of fascination for gem enthusiasts and jewelry lovers. Its durability, combined with its symbolic associations, ensures its continued popularity as a cherished gemstone for generations to come. The gem’s story, marked by initial misidentification and eventual recognition, underscores the importance of scientific understanding in appreciating the true value and beauty of these natural treasures.