Opal, a gemstone celebrated for its captivating play of color, holds a unique position in the world of gemstones. While associated with several months across different historical and modern charts, it is prominently featured as a birthstone for October and is notably recognized as Australia’s national gemstone. This article will delve into the history, geological origins, gemological properties, symbolism, and care of this mesmerizing gem, drawing exclusively from available sources.
History and Lore
The history of birthstones stretches back to biblical times, with origins believed to lie in the twelve gemstones adorning the Breastplate of Aaron, representing the twelve tribes of Israel. Over time, these stones became linked to the months of the year, forming the basis of the birthstone traditions known today. While ruby, emeralds, and diamonds have maintained prominence for centuries, opal’s inclusion as a birthstone evolved with more recent standardization efforts.
The modern birthstone list, as standardized in 1912 by the American National Retail Jewelers Association (now Jewelers of America), expanded the options for each birth month. Opal gained recognition as a primary birthstone for October alongside tourmaline. Earlier, traditional lists often featured different stones for each month, reflecting ancient beliefs about their powers and protective qualities.
Opal’s association with Australia is particularly strong. It is Australia’s national gemstone, a designation that underscores the country’s significant role in its mining and global supply.
Geological Formation and Sources
Opal is a hydrated amorphous form of silica, meaning it doesn’t have a crystalline structure like diamonds or rubies. Its formation is unique, typically occurring in sedimentary environments where silica-rich water seeps into cracks and voids in the earth. Over time, this water deposits silica, which hardens into opal. The play of color, opal’s most defining characteristic, is caused by the diffraction of light as it passes through microscopic spheres of silica within the stone.
The primary source of opal is Australia, specifically regions like South Australia. While other sources exist globally, Australia dominates the market. The gem is also found in other locations, though less commercially significant.
Gemological Properties
Opal’s properties differ significantly from those of more traditional gemstones. Its hardness ranges from 5.5 to 6.5 on the Mohs scale, making it softer and more susceptible to scratches than diamonds (hardness of 10) or sapphires (hardness of 9). This relative softness necessitates careful handling and consideration when setting opal in jewelry.
Opal is characterized by its variable color display, known as “play-of-color.” This phenomenon arises from the internal structure of the stone, as described above. The colors observed depend on the size and arrangement of the silica spheres. Opal exhibits a wide range of colors, including red, orange, yellow, green, blue, and violet.
While opal is often associated with a milky or translucent appearance, it can also be found in various forms, including black opal (with a dark body tone), white opal, and fire opal (which may lack play-of-color but exhibits a vibrant orange or red hue).
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been attributed with various symbolic meanings and metaphysical properties. While the sources do not detail extensive metaphysical beliefs specifically tied to opal, they do highlight its association with positive attributes. Garnet, for example, is linked to trust and friendship, while amethyst is believed to promote peace and courage. Opal, as a birthstone, is often seen as a symbol of hope, purity, and truth.
The sources indicate that birthstones, in general, are believed to offer protection and positive energy to those born in their corresponding month. Wearing a birthstone is considered a meaningful tradition and a stylish personal choice.
Care and Cleaning
Due to its relatively low hardness, opal requires careful handling and cleaning. It is susceptible to scratches and can be damaged by harsh chemicals or extreme temperatures. The sources recommend avoiding abrasive cleaners and ultrasonic cleaning devices. Instead, opal should be cleaned with a soft cloth and mild soapy water.
It is also advisable to protect opal from impacts and prolonged exposure to sunlight or heat, as these can cause it to crack or fade. Opal is best suited for earrings or pendants, where it is less likely to be subjected to abrasion.
December’s Diverse Gems
While this article focuses on opal as an October birthstone, it is important to note the evolving nature of birthstone lists. December, for example, has seen several changes over time. Originally associated with turquoise and lapis lazuli, the list was updated to include zircon and, more recently, tanzanite. The addition of tanzanite in 2002, spearheaded by Tiffany & Co., demonstrates the ongoing process of incorporating new and appealing gemstones into the birthstone tradition. The company launched a significant advertising campaign to promote the gem, which was discovered in Tanzania, hence its name. Tanzanite, like opal, exhibits high clarity and vivid colors, making it a desirable gemstone for jewelry.
The Evolution of Birthstone Charts
The standardization of birthstone lists has been a gradual process. The Traditional Birthstones Chart reflects historical and cultural beliefs, while the Modern Birthstone Chart incorporates more recent discoveries and preferences. The Official Birthstone Chart serves as a trusted guide for accurate gemstone listings, ensuring authenticity and industry standards. The choice of which chart to follow often depends on personal preference and cultural context. Some individuals may align with the traditional meanings and symbolism, while others may prefer the more contemporary options offered by the modern list.
Zodiacal Connections
Beyond monthly birthstones, some traditions link gemstones to zodiacal signs. For example, peridot is associated with the sign of Leo, believed to enhance its attributes of strength and vitality. This astrological connection adds another layer of meaning to gemstone selection, allowing individuals to choose stones that resonate with their personality and cosmic alignment.
Conclusion
Opal, with its mesmerizing play-of-color and unique geological origins, stands as a captivating gemstone. Its status as Australia’s national gemstone and a prominent birthstone for October underscores its cultural and aesthetic significance. While requiring careful handling due to its relative softness, opal continues to enchant jewelry enthusiasts and collectors worldwide. The evolving history of birthstones, from ancient traditions to modern standardization, reflects a continuing fascination with the beauty, symbolism, and enduring appeal of these precious gems.