December is a unique month in the world of birthstones, distinguished by not one, but three captivating gems: turquoise, tanzanite, and zircon. While turquoise holds the longest and most consistent association with the month, the inclusion of tanzanite and zircon reflects the evolving nature of birthstone traditions and offers a diverse palette of color and symbolism for those born in the final month of the year. These stones, each with a rich history and distinct properties, embody the spirit of December – a time of change, celebration, and warm reunions.
History and Lore
The story of December’s birthstones is one of shifting traditions. Originally, ruby was associated with December, a designation rooted in early Biblical gemstone lists. However, by the 19th century, turquoise began to emerge as the primary December birthstone, popularized by Tiffany & Co.’s 1870 “Gregorian Birthstone Poems” pamphlet. This association continued with the National Association of Jewellers in 1912, solidifying turquoise’s place as the traditional December gem. Lapis lazuli was also listed as an alternative in 1912.
The 20th and 21st centuries witnessed the addition of zircon in 1952 and, more recently, tanzanite in 2002, expanding the options for December babies. This evolution highlights how birthstone lists are not static, but rather reflect changing tastes, discoveries, and marketing influences.
Turquoise boasts an exceptionally long history, dating back to ancient civilizations. As early as 5500 BC, Egyptians were crafting jewelry from turquoise, calling it mefkat, meaning “joy,” and associating it with the sky goddess Hathor. The stone held significance for protection and status. Ancient Persians, referring to turquoise as pērōzah (“victory”), believed it to be heavenly and adorned it on turbans, weapons, and mosques. Ancient Greeks and Romans also valued turquoise, crafting beads, necklaces, and rings from the gem. Aztecs considered turquoise sacred, believing it embodied fire and burying rulers with it in their mouths. Native American tribes similarly prized turquoise for ceremonial purposes, talismans, and even as a form of currency, with the Apache believing it enhanced the accuracy of their bows.
Geological Formation and Sources
Turquoise, a hydrated phosphate of copper and aluminum, forms through a secondary enrichment process in arid regions. It is typically found in the vicinity of copper deposits, where groundwater interacts with mineralized rock. Significant sources of turquoise include Iran, historically prized for its intense “robin’s egg blue” variety, and more recently, the United States, particularly Arizona and Nevada. Historically, New Mexico was a major producer, but Arizona’s Kingman mine and the now-closed Sleeping Beauty mine have become prominent sources.
Zircon, a zirconium silicate, forms in igneous rocks and metamorphic rocks. It is found in a variety of colors, but blue zircon is the variety most often associated with December.
Tanzanite, a relatively recent discovery, is a blue to violet variety of the mineral zoisite. It is found exclusively in the Merelani Hills of northern Tanzania, near the foothills of Mount Kilimanjaro. This limited geographical origin contributes to its rarity and value.
Gemological Properties
The gemological properties of these three birthstones differ significantly.
Turquoise: Its color ranges from sky blue to greenish-blue, often with matrix (veins of other minerals) present. Turquoise typically lacks strong brilliance and is relatively soft, with a Mohs hardness of 5 to 6.
Zircon: Zircon exhibits a higher hardness than turquoise, ranging from 6 to 7.5 on the Mohs scale. Blue zircon is particularly valued, and its brilliance is notable.
Tanzanite: Tanzanite also has a Mohs hardness of 6 to 7, making it moderately durable. Its color ranges from blue to violet, and it exhibits strong trichroism, meaning it displays different colors when viewed from different angles. Most tanzanite undergoes heat treatment to enhance its blue to violet hues, a process that results in a permanent color change.
Here's a table summarizing key properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Color | Notable Features |
|---|---|---|---|---|
| Turquoise | CuAl6(PO4)4(OH)8·4H2O | 5-6 | Sky blue to greenish-blue | Often contains matrix |
| Zircon | ZrSiO4 | 6-7.5 | Typically blue | High brilliance |
| Tanzanite | Ca2Al3(SiO4)3(OH) | 6-7 | Blue to violet | Strong trichroism, often heat-treated |
Symbolism and Metaphysical Beliefs
Throughout history, each of these December birthstones has been imbued with symbolic meaning. Turquoise has long been associated with protection, good fortune, and peace. In Tibet, it is considered a national treasure believed to ward off evil. In European tradition, gifting a turquoise ring symbolized “forget me not.”
While specific metaphysical beliefs surrounding zircon and tanzanite are less extensively documented in the provided sources, turquoise’s rich history suggests a broader tradition of attributing protective and beneficial powers to gemstones.
Care and Cleaning
Due to its relative softness, turquoise requires careful handling. It is susceptible to scratching and can be damaged by harsh chemicals. Warm, soapy water is the recommended cleaning method.
Zircon and tanzanite, with their higher hardness, are more durable but still require care. Tanzanite, in particular, is sensitive to sudden temperature changes and should not be exposed to high heat. Ultrasonic and steam cleaners are not recommended for tanzanite. Warm, soapy water is the best method for cleaning both zircon and tanzanite. Tanzanite is best set in earrings or pendants to minimize the risk of damage from daily wear in a ring.
Conclusion
The December birthstones – turquoise, tanzanite, and zircon – represent a fascinating blend of ancient tradition and modern discovery. Turquoise, with its millennia-long history and association with protection and good fortune, remains a cornerstone of December’s gemological heritage. The addition of tanzanite and zircon provides a wider range of color and appeal, reflecting the evolving nature of birthstone lore. Whether drawn to the serene blue of turquoise, the vibrant violet of tanzanite, or the brilliant sparkle of zircon, those born in December have a trio of beautiful and meaningful gemstones to choose from, each embodying the spirit of the season and the promise of a new year.