October is unique among the calendar months in possessing two recognized birthstones: pink tourmaline and opal. Both gemstones offer a stunning array of colors and have captivated cultures for centuries, representing hope, purity, and the vibrant beauty of the autumn season. This article will explore the history, geological origins, gemological properties, symbolism, and care of these fascinating October birthstones, drawing solely from available sources.
History and Lore
The story of opal’s name is somewhat shrouded in mystery, with potential origins in both the Greek opallios, meaning “to see a change in color,” and the Sanskrit upala, translating to “precious stone.” The Roman term opalus is first recorded around 250 BC, further tracing the gem’s long history. Ancient Greeks believed opal bestowed the gift of prophecy and protection from disease, while Europeans considered it a symbol of purity, hope, and truth. For centuries, opal was thought to embody the virtues of all colored stones.
Tourmaline’s history is also rich, though its identification as a distinct gem is more recent. In the 1600s, Dutch traders brought colored tourmalines from Sri Lanka to Europe, initially mistaking them for zircons. It wasn’t until around 1703 that the distinction between tourmaline and zircon was established, specifically recognizing the black schorl variety as a unique mineral. Historically, pink and red tourmalines were often confused with rubies, a testament to their similar coloration. Alchemists valued tourmaline for its electric properties – the ability to attract particles when heated – believing it was closely related to the philosopher’s stone, a mythical substance capable of granting enlightenment.
A popular, though potentially unfounded, superstition surrounding opal arose from Sir Walter Scott’s 1829 novel Anne of Geierstein, which linked the gem to bad luck for those not born in October. However, throughout much of history, opal was regarded as a lucky and magical gem.
Geological Formation and Sources
Opal is a mineraloid, formed by the gradual heating of silica gel within cracks in rocks. It exists in two primary varieties: precious opal, which exhibits play-of-color, and common opal, which does not. The vast majority of the world’s opal supply originates from Australia, accounting for over 95% of production. Within Australia, notable sources include Lightning Ridge, known for its black opal; Coober Pedy and White Cliffs, sources of white opal; and Queensland, where boulder opal – characterized by its reddish hue due to ironstone inclusions – is found. Mexico, particularly the state of Querétaro, is also a significant source of fire opal, often translucent with yellow to red base colors.
Tourmaline, unlike opal, is a crystalline mineral belonging to a complex group of boron silicate minerals. Three main species exist: schorl, dravite, and elbaite. Schorl is typically black or brownish-black, dravite ranges from dark yellow to brownish-black, and elbaite exhibits the widest range of colors, including colorless, blue, green, and pinkish-red. Historically, Sri Lanka was a key source of tourmaline, with gems brought to Europe by the Dutch East India Company. Brazilian discoveries in the 1980s and 1990s significantly expanded the availability of tourmaline, introducing intense new hues to the market.
Gemological Properties
Tourmaline’s hardness ranges from 7 to 7.5 on the Mohs scale, making it a relatively durable gemstone, comparable to citrine and other quartz varieties. This durability makes it a suitable choice for rings and everyday wear. It is notable for its exceptional range of colors, from rich reds and greens to pastel pinks and blues.
Opal, in contrast, has a lower hardness, measuring between 5.5 and 6 on the Mohs scale. This makes it more susceptible to scratches and chipping, and therefore best suited for pendants and earrings where it is less likely to be damaged. The defining characteristic of precious opal is its “play-of-color,” a shifting display of rainbow hues caused by the diffraction of light within its internal structure. This phenomenon has been likened to fireworks, galaxies, and volcanoes. Opal can be opaque, translucent, or nearly transparent.
Here's a table summarizing the key gemological properties:
| Property | Tourmaline | Opal |
|---|---|---|
| Hardness (Mohs) | 7 - 7.5 | 5.5 - 6 |
| Chemical Formula | Complex Boron Silicate | Hydrated Silica |
| Color | Wide range | Varied, Play-of-Color |
| Transparency | Transparent to Opaque | Opaque to Translucent |
| Luster | Vitreous | Vitreous/Resinous |
Symbolism and Metaphysical Beliefs
Pink tourmaline is closely associated with emotions and the heart chakra, representing love and emotional healing. The gem’s ability to attract particles when heated was seen by alchemists as a connection to the philosopher’s stone and the pursuit of enlightenment.
Opal is believed to bring confidence and hope to the wearer. Historically, it was considered a symbol of purity, hope, and truth. Bedouins believed opal held lightning and fell from the sky during thunderstorms. The name “opal” itself, derived from the Greek opallios, reflects its characteristic ability to display a change in color.
Care and Cleaning
Due to its greater hardness, tourmaline is relatively easy to care for. It can be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and harsh chemicals.
Opal requires more delicate care. Its lower hardness makes it susceptible to scratches. Cleaning should be done with a soft cloth and mild soapy water. Avoid ultrasonic cleaners, harsh chemicals, and prolonged exposure to heat or direct sunlight, as these can cause cracking or fading. Opal rings should be worn with care to avoid impacts.
Conclusion
October’s birthstones, pink tourmaline and opal, represent a captivating duality. Tourmaline offers durability and a wide spectrum of colors, while opal enchants with its unique play-of-color and historical mystique. Both gemstones carry rich symbolism and have been treasured by cultures for centuries. Whether chosen for their beauty, their perceived metaphysical properties, or their connection to the month of October, these gems continue to inspire and delight.