December is unique among the months, boasting not one, but three recognized birthstones: turquoise, tanzanite, and zircon. Each gem carries its own distinct history, aesthetic qualities, and symbolic weight, offering a diverse range of options for those born in the final month of the year. This article will explore the origins, properties, and cultural significance of these December birthstones, drawing upon historical accounts and gemological understanding.
History and Lore
The concept of associating specific gemstones with each month has deep roots in history, tracing back to the biblical breastplate of Aaron, as described in the Book of Exodus. This breastplate, adorned with twelve gemstones, was said to represent the twelve tribes of Israel, with each stone corresponding to a birth month. While the exact mapping between ancient stones and modern birthstones is debated, this tradition laid the foundation for the birthstone system we know today. The association of gemstones with specific months evolved over time, with different cultures and historical periods assigning varying stones to each month.
Turquoise, arguably the oldest of the three December birthstones, holds a particularly rich and extensive history. For thousands of years, it has been prized by cultures across the globe, including the Ancient Egyptians, Persians, Chinese, Aztecs, and Native North Americans. These civilizations revered turquoise as a symbol of wisdom, nobility, and the power of immortality, utilizing it in adornments believed to bestow power, luck, and protection.
Tanzanite and zircon, while possessing their own histories, are comparatively more recent additions to the December birthstone list. The American Gem Society expanded the traditional list to include alternative gemstones, recognizing tanzanite, turquoise, and zircon for December.
Geological Formation and Sources
Turquoise is a secondary mineral, meaning it forms from the alteration of existing minerals. It is typically found in arid regions, forming in volcanic rocks and sedimentary deposits. The presence of copper, aluminum, and hydrated phosphate minerals is crucial to its formation. Significant sources of turquoise include the southwestern United States, Iran, and China.
Tanzanite, discovered relatively recently in 1967, is found exclusively in the Merelani Hills of northern Tanzania, hence its name. It forms in metamorphic rocks and is a variety of the mineral zoisite. Its unique trichroism – displaying three different colors depending on the viewing angle – contributes to its desirability.
Zircon, a zirconium silicate mineral, is found in a variety of geological settings, including igneous, metamorphic, and sedimentary rocks. It occurs in various colors, but the blue varieties are most commonly associated with December. Sources of zircon include Cambodia, Sri Lanka, and Australia.
Gemological Properties
Turquoise: This opaque gemstone exhibits a unique shade of blue, often with green undertones. Its color is influenced by the presence of copper and iron. The presence of veining or mottled webbing, typically in cream or brown, is a characteristic feature that enhances its character. Turquoise is relatively soft, with a Mohs hardness of 5-6, requiring careful handling to avoid scratches.
Tanzanite: This gemstone is known for its intense violet-blue color, though it can also appear blue, violet, or even reddish-purple. Its pleochroism is a notable characteristic, displaying different colors when viewed from different angles. Tanzanite has a Mohs hardness of 6.5-7, making it moderately durable. Its chemical composition is Ca2Al3(SiO4)3(OH).
Zircon: Zircon occurs in a wide range of colors, including brown, red, yellow, green, and blue. Blue zircon is often produced by heat-treating colorless zircon. It boasts a relatively high refractive index, contributing to its brilliance. Zircon has a Mohs hardness of 6.5-7.5, making it reasonably durable.
The following table summarizes the key gemological properties:
| Property | Turquoise | Tanzanite | Zircon |
|---|---|---|---|
| Chemical Formula | CuAl6(PO4)4(OH)8·4H2O | Ca2Al3(SiO4)3(OH) | ZrSiO4 |
| Mohs Hardness | 5-6 | 6.5-7 | 6.5-7.5 |
| Color | Blue, Blue-Green | Violet-Blue | Various, often Blue |
| Transparency | Opaque | Transparent | Transparent |
| Luster | Waxy | Vitreous | Adamantine |
Symbolism and Metaphysical Beliefs
Throughout history, each of these December birthstones has been imbued with symbolic meaning. Turquoise, as previously mentioned, was considered a sacred stone by many ancient cultures, representing wisdom, nobility, and protection. It was believed to bring good fortune and ward off negative energy.
Tanzanite, a more modern discovery, is often associated with transformation, intuition, and spiritual awareness. Its vibrant color is thought to stimulate creativity and enhance psychic abilities.
Zircon, particularly the blue variety, is believed to promote wisdom, honor, and prosperity. It has also been associated with calming energies and protection from nightmares.
Care and Cleaning
Due to its relative softness, turquoise requires gentle care. It should be protected from scratches and harsh chemicals. Cleaning can be done with a soft cloth and mild soapy water. Avoid ultrasonic cleaners and steam cleaners.
Tanzanite is more durable than turquoise but still requires careful handling. It can be cleaned with warm, soapy water and a soft brush. Avoid harsh chemicals and ultrasonic cleaners.
Zircon is reasonably durable and can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners can be used with caution.
Conclusion
December’s birthstones – turquoise, tanzanite, and zircon – represent a captivating blend of history, beauty, and symbolism. From the ancient reverence for turquoise to the modern allure of tanzanite and the enduring appeal of zircon, these gemstones offer a diverse range of choices for those seeking a meaningful connection to their birth month. Understanding their unique properties and historical significance ensures that these gems will be cherished for generations to come.