December is unique among the months, possessing not one, but two recognized birthstones: blue zircon and tanzanite. Both stones offer a vibrant blue hue, though their origins, histories, and gemological properties differ significantly. This article will explore the characteristics, history, and symbolism of these December birthstones, drawing upon established gemological understanding and historical context.
History and Lore
The association of gemstones with specific months dates back millennia. Early examples of birthstone use appear in biblical texts, such as the Book of Exodus, which references twelve stones. These early associations were often linked to astrological beliefs, with gemstones believed to reflect the energies of the stars and planets. Ancient and medieval astrologers assigned gems to the planets, believing these gems could connect individuals to the heavens and strengthen their personal fortitude. Initially, zodiac stones and birthstones were largely synonymous, but over time, the lists diverged, with modern birthstones including many precious gems while zodiac stones often lean towards semi-precious varieties.
The standardization of birthstone lists is a relatively recent phenomenon. In 1912, the National Association of Jewelers created a modern list, which has remained largely unchanged since. This list, and subsequent updates, formalized the connection between specific gemstones and birth months, solidifying their role in cultural traditions and gift-giving practices. Updates to the list occurred in 1952, with Alexandrite added for June and pink tourmaline for October, and again in 2016, with spinel added as a birthstone for August.
While turquoise was traditionally associated with December, blue zircon and, more recently, tanzanite have become the primary modern birthstones for this month. Tanzanite’s inclusion is particularly noteworthy, as it was only added in 2002, largely due to a successful marketing campaign by Tiffany & Co., who recognized its international appeal.
Geological Formation and Sources
Blue zircon’s origins are diverse, with significant production occurring in Sri Lanka and Australia. Zircon itself is a relatively common mineral, but gem-quality blue zircon is less frequently found. The gem is often heat-treated to enhance or produce variations in color, demonstrating the influence of human intervention in bringing out its aesthetic qualities.
Tanzanite, in contrast, is exceptionally rare, found commercially only in the Merelani Hills of Tanzania. Its discovery in Tanzania led to its naming, and its limited source contributes to its value and desirability. The geological conditions required for tanzanite formation are highly specific, making it a truly unique gemstone.
Gemological Properties
Zircon exhibits a hardness ranging from 6 to 7.5 on the Mohs scale, making it suitable for everyday jewelry with proper care. Its chemical composition allows for a wide range of colors, including red, orange, brown, yellow, green, and blue. The vibrant blue color is particularly prized.
Tanzanite also possesses a hardness of 6 to 7 on the Mohs scale. It is known for its high clarity and vivid colors, often displaying trichroism – exhibiting different colors when viewed from different angles. This pleochroism contributes to its captivating appearance. Tanzanite is resistant to heat, light, and common chemicals, but is best suited for use in earrings or pendants due to its potential for cleavage.
The following table summarizes key gemological properties:
| Gemstone | Hardness (Mohs) | Color | Primary Sources |
|---|---|---|---|
| Blue Zircon | 6 - 7.5 | Blue | Sri Lanka, Australia |
| Tanzanite | 6 - 7 | Vivid Blue/Violet | Merelani Hills, Tanzania |
Symbolism and Metaphysical Beliefs
Birthstones are believed to hold symbolic affiliations to the month of birth, showering those born in that month with fortune and strength. The specific meanings associated with each stone vary across cultures and traditions. While the sources do not detail specific symbolism for blue zircon, the broader category of zircon is associated with prosperity and wisdom. Tanzanite, with its relatively recent recognition as a birthstone, is linked to peace and calmness.
Beyond birthstone associations, gemstones have historically been connected to the days of the week, with each day linked to a specific stone believed to absorb planetary energies. For example, turquoise, sapphire, or lapis lazuli are associated with Wednesday, offering protection from negativity.
Care and Cleaning
Given their similar hardness levels, both blue zircon and tanzanite require careful handling. They are susceptible to scratching from harder materials and should be stored separately from diamonds and other durable gemstones. Cleaning can be performed with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and harsh chemicals, as these can damage the stones. Regular cleaning will help maintain their brilliance and luster.
Zodiac Birthstones
The concept of zodiac birthstones offers an alternative way to select gemstones based on astrological sign. Each zodiac sign is associated with specific stones, reflecting the perceived influence of the stars on personality and destiny. For example, red jasper is linked to Aries, while rose quartz is associated with Taurus. This system provides a broader range of options, including semi-precious stones, and allows individuals to choose a gem that resonates with their astrological profile.
Conclusion
Blue zircon and tanzanite represent the captivating beauty and rich history of December’s birthstones. While zircon boasts a long tradition and diverse origins, tanzanite’s recent discovery and limited source contribute to its unique allure. Both stones offer a vibrant blue hue and symbolize peace, wisdom, and prosperity. Their inclusion in jewelry designs provides treasured and sentimental gifts, connecting wearers to both the natural world and the enduring traditions of gemological lore.