October is unique among the months, blessed with not one, but two recognized birthstones: the captivating opal and the richly colored tourmaline. While opal holds the distinction as the traditional October birthstone, tourmaline was added as a modern alternative in 1952, reflecting evolving tastes and gemstone availability. Both stones offer a dazzling array of colors and possess a fascinating history, making them cherished gems for those born in the tenth month. This article will delve into the history, geological origins, gemological properties, symbolism, and care of these two remarkable gemstones.
History and Lore
The story of opal stretches back to ancient times. Its name is believed to originate from the Sanskrit word upala, meaning “precious stone,” and was later adopted by the Romans as opalus. Ancient civilizations attributed various powers to opal. Ancient Greeks believed it bestowed the gift of prophecy and offered protection from disease, naming it opallios, meaning “to see a change in color.” Europeans long considered opal a symbol of purity, hope, and truth, and for centuries, it was thought to embody the virtues of all colored stones. Bedouins held the belief that opal contained lightning and fell to earth during thunderstorms.
Tourmaline’s history, while also ancient, has a slightly more convoluted beginning. The gem was first discovered off the West Coast of Italy by Dutch traders in the late 1600s or early 1700s, though its presence was known for centuries prior. In the 1500s, a Spanish conquistador in Brazil mistakenly identified green tourmaline as emerald, leading to initial confusion about its identity. It wasn’t until the 1800s that mineralogists formally recognized tourmaline as a distinct mineral species. The name “tourmaline” itself comes from the Sinhalese words turamali or toramalli, meaning “stone with mixed colors.”
The addition of tourmaline as an October birthstone in 1952 was a deliberate decision by the National Association of Jewelers. Opal was perceived as too feminine by some, and concerns regarding its durability prompted the inclusion of the more robust tourmaline, particularly pink tourmaline, to broaden the options for October babies.
Geological Formation and Sources
Opal is a unique gemstone formed from hydrated amorphous silica. The commonly held belief is that opals are formed from rain that seeps into cracks and crevices in the earth. As the water travels downwards, it dissolves silica from the surrounding sandstone and other rocks. When the water dries, it leaves behind microscopic spheres of silica, which eventually form the opal. The “play-of-color” seen in precious opals is caused by the diffraction of light as it passes through these microscopic silica spheres.
The majority of the world’s opal is mined in Australia, which accounts for the vast majority of production. Other notable sources include Ethiopia, Mexico, and the United States.
Tourmaline, on the other hand, is a complex borosilicate mineral. It forms in igneous and metamorphic rocks, often in pegmatites, which are coarse-grained igneous rocks. The diverse colors of tourmaline are attributed to the presence of various trace elements within its crystal structure.
Tourmaline is found in a wide range of locations globally. Brazil was a significant early source, with green tourmaline initially mistaken for emerald. Other important mining locations include Sri Lanka, Africa, Afghanistan, Pakistan, and the United States. The rare and highly prized Paraiba tourmaline, known for its neon blue and green hues, is primarily sourced from Brazil and Mozambique.
Gemological Properties
Both opal and tourmaline exhibit distinct gemological properties. Opal is characterized by its unique play-of-color, a phenomenon that sets it apart from most other gemstones. It typically has a hardness of 5-6.5 on the Mohs scale, making it relatively softer and more susceptible to scratches and damage. Opal is composed of hydrated silica (SiO₂·nH₂O), with a variable water content. It is amorphous, meaning it lacks a defined crystal structure.
Tourmaline, in contrast, boasts a Mohs hardness of 7-7.5, making it significantly more durable than opal and suitable for everyday wear. Its chemical formula is complex, varying depending on the specific type of tourmaline, but generally represented as (Na,Ca)(Al,Li,Mg)₃(Al,Fe,Mn)₆(BO₃)₃(Si₆O₁₈)(OH)₄. Tourmaline crystallizes in the trigonal system, forming prismatic, elongated crystals. As its name suggests, tourmaline is renowned for its wide range of colors, including pink, green, blue, purple, and even multi-colored varieties.
The following table summarizes key gemological properties:
| Property | Opal | Tourmaline |
|---|---|---|
| Chemical Formula | SiO₂·nH₂O | (Na,Ca)(Al,Li,Mg)₃(Al,Fe,Mn)₆(BO₃)₃(Si₆O₁₈)(OH)₄ |
| Hardness (Mohs) | 5-6.5 | 7-7.5 |
| Crystal System | Amorphous | Trigonal |
| Specific Gravity | 1.98 – 2.15 | 3.06 – 3.10 |
| Notable Feature | Play-of-Color | Wide Color Variety |
Symbolism and Metaphysical Beliefs
Throughout history, both opal and tourmaline have been imbued with symbolic meaning. Opal has long been associated with luck, hope, and spiritual awakening. Ancient cultures believed it could bestow prophetic abilities and offer protection from disease. In more recent times, opal is often linked to creativity, imagination, and emotional expression. Its unique play-of-color is seen as a reflection of the multifaceted nature of the individual.
Tourmaline, similarly, carries a rich symbolism. It is often associated with love, prosperity, and harmony. Pink tourmaline, in particular, is considered a stone of love and compassion. Different colors of tourmaline are believed to possess different properties; for example, green tourmaline is thought to promote healing and growth, while black tourmaline is often used for grounding and protection. Tourmaline is also believed to enhance energy, vitality, and personal power.
Care and Cleaning
Due to its lower hardness, opal requires careful handling and cleaning. It is susceptible to scratches and can be damaged by harsh chemicals or extreme temperatures. Opal should be cleaned with a soft cloth and mild soapy water. Avoid ultrasonic cleaners and steam cleaners, as these can cause damage. It’s best to store opal jewelry separately from harder gemstones to prevent scratching.
Tourmaline, with its greater durability, 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 it’s always best to exercise caution. Avoid exposing tourmaline to harsh chemicals or prolonged sunlight, as this can fade its color.
Conclusion
Opal and tourmaline, the captivating birthstones of October, offer a beautiful blend of history, geological wonder, and symbolic meaning. While opal, the traditional birthstone, enchants with its iridescent play-of-color and ancient lore, tourmaline provides a durable and vibrant alternative, representing love, prosperity, and a spectrum of energetic qualities. Both gemstones are a testament to the beauty and diversity of the natural world, making them cherished treasures for those born under the October sky.