Opal, with its captivating play-of-color and ethereal beauty, stands as one of the most enigmatic and visually dynamic gemstones in the mineral kingdom. Designated as the birthstone for October, it has been revered for centuries, yet simultaneously shadowed by a persistent cloud of superstition. A common belief suggests that opal is an unlucky talisman for anyone not born in October, a notion that has sparked debate among jewelers, gemologists, and enthusiasts alike. This article delves into the rich history, geological origins, and scientific properties of opal, while critically examining the folklore that has shaped its reputation. By separating centuries-old myth from modern gemological understanding, we can fully appreciate opal not as a harbinger of misfortune, but as a masterpiece of nature’s artistry, worthy of adornment by all who are drawn to its iridescent light.
History and Lore: The Birth of a Superstition
The history of opal is steeped in legend and cultural significance, with civilizations across the globe attributing powerful properties to this unique stone. Ancient Arabic legends held that opals fell from the heavens during flashes of lightning, imbuing them with celestial fire. The Greeks believed opals granted their owners the gift of prophecy and served as a protective shield against disease. Across many cultures, opal has been a long-standing symbol of hope, clarity, purity, faithfulness, love, goodness, and truth.
However, opal’s journey to becoming October’s birthstone is a relatively modern development. The concept of birthstones, where a specific gem is assigned to each month, gained widespread popularity in the 18th and 19th centuries. During this period, opal was officially designated for October. It is crucial to understand that this assignment was initially intended as a symbolic linkage, not a rigid rule or a superstition. Birthstones were meant to carry meaning about traits associated with people born in each month, but they were never intended to dictate who could or could not wear them. The idea that birthstones are exclusive to their corresponding months is a later, and largely unfounded, interpretation.
The specific superstition that opal is unlucky for anyone not born in October is a more recent and culturally specific myth. Its origins are complex, but it is widely attributed to a blend of factors. One significant catalyst was Sir Walter Scott’s 1829 novel, Anne of Geierstein, or The Maiden of the Mist. In the novel, an enchanted princess wears an opal clasp in her hair that seems to take on a life of its own, with catastrophic consequences. The dramatic portrayal of the stone in this popular work is believed to have significantly tarnished opal’s reputation in the public imagination, linking it to misfortune and doom.
This literary influence was compounded by practical challenges faced by opal jewelry in the 19th century. At that time, opals were often set in vegetable-based oils. These settings were susceptible to environmental changes; exposure to fluctuations in temperature or humidity could cause the oil to dry out, temporarily diminishing the opal’s play-of-color. This observable phenomenon likely fueled the myth that opal would lose its color and, by extension, its luck if worn by the wrong person. Furthermore, the color black—found in prized Australian black opal—was historically associated with death and evil in many Western cultures, leading to the stone being sometimes called a “witch stone” and considered particularly unlucky.
Geological Formation and Sources
Opal is not a typical crystalline gemstone like sapphire or diamond. It is a form of amorphous silica, composed of microscopic spheres of silica (SiO₂·nH₂O) that have settled into a solid mass. The famous play-of-color, or opalalescence, is created when light interacts with these spheres and the spaces between them, causing diffraction of light into spectral colors. The size of the spheres determines the color displayed; larger spheres produce reds and oranges, while smaller spheres yield blues and violets.
Opal forms in environments where silica-rich water seeps into cracks and voids in rocks. Over long periods, the water evaporates, leaving behind deposits of silica. This process typically occurs in two main geological settings: 1. Sedimentary Deposits: This is the most common and economically significant source. Silica is deposited in areas where ancient bodies of water, such as lakes or seas, have receded, leaving behind layers of silica gel that later solidify. Australia is the world’s premier source for precious opal, particularly from regions like Lightning Ridge, Coober Pedy, and Mintabie, which are renowned for producing stunning black opal, white opal, and crystal opal. 2. Volcanic Deposits: In some cases, opal can form in volcanic regions where silica-rich gases and fluids precipitate in cavities within volcanic rock.
The sources of opal are geographically concentrated, with Australia dominating the global market for high-quality precious opal. Other notable sources include Ethiopia, which has gained recognition for its vibrant hydrophane opal, and Mexico, known for its fire opal. The specific geological conditions of each region contribute to the unique characteristics of the opals found there.
Gemological Properties
Understanding the physical and chemical properties of opal is essential for appreciating its unique character and for its proper care. The following table summarizes key gemological data for precious opal, based on established standards.
| Property | Description |
|---|---|
| Chemical Formula | SiO₂·nH₂O (Hydrated Silicon Dioxide) |
| Crystal System | Amorphous (non-crystalline) |
| Hardness (Mohs Scale) | 5.5 to 6.5 |
| Refractive Index | 1.37 - 1.47 (typically around 1.45) |
| Specific Gravity | 1.98 - 2.25 |
| Luster | Vitreous (glass-like) to resinous; can be waxy. |
| Transparency | Opaque to translucent. |
| Key Feature | Play-of-Color: The iridescent display of spectral colors caused by light diffraction through the silica spheres. |
A critical point often misunderstood is opal’s hardness. Rated between 5.5 and 6.5 on the Mohs scale, it is softer than many popular gemstones like quartz (7) or topaz (8). This does not mean opal is inherently fragile or unusable for jewelry; rather, it indicates a need for mindful setting and care. As one source notes, some customers have enjoyed wearing their opals daily for over 30 years, demonstrating that with proper handling, opal is sufficiently durable for regular wear. Its durability is comparable to that of moonstone (6 - 6.5).
The chemical composition includes a variable water content, which is a crucial factor in its care. Opal can contain up to 21% water by weight. This makes it susceptible to thermal shock and dehydration if exposed to sudden, extreme temperature changes or intense, direct heat, which can cause cracking.
Symbolism and Metaphysical Beliefs
Beyond its physical beauty, opal has been attributed with a rich tapestry of symbolic meanings and metaphysical powers throughout history. As previously mentioned, ancient cultures associated it with prophecy, protection from disease, and virtues like hope, purity, and love. In modern crystal healing and metaphysical circles, opal is often linked to emotional balance, creativity, and inspiration. Its ever-changing play-of-color is seen as a reflection of the multifaceted nature of human emotion and thought.
The belief that opal carries bad luck is a specific and relatively narrow interpretation within this broader symbolic landscape. Modern astrologers and gemologists overwhelmingly dismiss this superstition as unfounded. There is no scientific, statistical, or anecdotal evidence linking opal to misfortune or accidents for individuals not born in October. The concept that a gemstone’s power is exclusively tied to a birth month is not supported by formal gemology. In fact, birthstone traditions vary across cultures; for example, opal is sometimes considered the birthstone for April or June in other systems, further undermining the idea of an exclusive October claim.
The “luck” associated with opal is far more universal. Its rainbow colors are interpreted as symbols of hope and the full spectrum of human experience. As a gemstone, its value lies in its unique aesthetic and geological rarity, not in any prescribed astrological mandate.
Care and Cleaning
Given its specific physical properties, opal requires particular care to maintain its beauty and integrity. The following guidelines are based on its hardness, water content, and structure:
- Protection from Impact and Pressure: Due to its hardness of 5.5 to 6.5, opal can be scratched by harder materials (e.g., diamonds, sapphires, even dust with high quartz content). It is also somewhat brittle and can be chipped or cracked if struck against a hard surface. For rings, which are subject to daily knocks, protective settings (like bezel settings) are recommended. Choosing shapes with rounded edges, such as oval, round, or pear-shaped cabochons, can help prevent chipping.
- Avoiding Thermal Shock: Never expose opal to sudden temperature changes. Do not wear it in saunas, hot tubs, or while cooking over a high flame. Cleaning with steam or ultrasonic cleaners is strictly discouraged, as the heat and vibrations can cause internal fractures.
- Cleaning Method: The safest way to clean opal jewelry is with warm, soapy water and a soft brush. Gently scrub the stone and setting, then rinse thoroughly with lukewarm water and pat dry with a soft, lint-free cloth. Avoid harsh chemicals, detergents, and solvents, which can damage the stone or its setting.
- Storage: Store opal jewelry separately from other pieces to prevent scratching. A soft pouch or a lined jewelry box is ideal. For long-term storage, especially in very dry climates, some experts suggest placing a small, damp (not wet) cloth near the opal (but not touching it) to maintain a stable humidity level, though this is not necessary for most modern, well-set opals.
- Setting Material: Modern opal jewelry is typically set in protective materials like resin, glass, or quartz, which help prevent dehydration. Settings in sterling silver, gold, or platinum are also common and provide good protection. Avoid low-quality plastics or poorly constructed settings.
Conclusion
Opal’s reputation as an unlucky stone for those not born in October is a myth rooted in historical literature, outdated practical challenges with early jewelry, and cultural biases against the color black. Modern gemology and expert consensus firmly reject this superstition. Opal’s true value is found in its extraordinary optical phenomenon—play-of-color—a natural wonder that has fascinated humanity for millennia. Its symbolic meanings of hope, creativity, and love are universal, transcending arbitrary birth month boundaries. With proper care and an understanding of its properties, opal is a durable and breathtaking gemstone suitable for anyone who appreciates its unique beauty. It is not a stone of exclusive fortune, but a radiant testament to nature’s artistry, inviting all admirers to wear its light.