December boasts a remarkable selection of birthstones – turquoise, tanzanite, and zircon – offering a spectrum of blues and a rich tapestry of history and lore. While earlier traditions assigned ruby to the month, the modern list has evolved, with turquoise holding the most consistent position alongside the more recent additions of tanzanite and zircon. Each of these gemstones possesses unique characteristics, making December a particularly vibrant month for gemstone enthusiasts.
Historical and Cultural Significance
The association of gemstones with specific months dates back to ancient times, initially linked to the breastplate of Aaron, the High Priest of the Israelites, which featured twelve stones representing the tribes of Israel. Early birthstone lists varied, with ruby initially designated for December. However, by the 19th century, changes began to occur. Tiffany & Co.’s 1870 “Gregorian Birthstone Poems” pamphlet listed turquoise as a December birthstone, a designation that gained traction. The National Association of Jewellers (now Jewellers of America) initially affirmed turquoise in 1912, later adding lapis lazuli as an alternative. Zircon was added to the list in 1952 by the Jewelry Industry Council of America, and tanzanite was the most recent addition in 2002. This evolution reflects changing preferences and the discovery of new and captivating gemstones.
Turquoise, in particular, has a long and storied history, cherished for millennia across numerous cultures. Ancient Egyptians adorned themselves with turquoise, and Chinese artisans were carving it over 3,000 years ago. It was believed to possess protective powers, safeguarding wearers from falls and misfortune. Hindu mystics associated it with wealth and good fortune.
Geological Formation and Sources
Turquoise is a semi-translucent to opaque gem, typically ranging in color from blue to green, often exhibiting distinctive veins of matrix – remnants of the host rock. It forms in semi-humid and dry environments near water tables, where chemicals seep through rocks via rainwater and groundwater. The blue hue is primarily attributed to copper content, while iron contributes to the green coloration. The origin of turquoise is not explicitly detailed beyond its formation process.
Zircon, ranging from 6 to 7.5 on the Mohs scale of hardness, is found in association with sapphire deposits. Notable sources include Sri Lanka, Australia, Myanmar, Vietnam, and Cambodia.
Tanzanite’s geological origins and specific mining locations are not detailed in the provided sources.
Gemological Properties
Each of December’s birthstones exhibits distinct gemological properties. Turquoise is a copper aluminum phosphate, characterized by its opaque nature and veined appearance. Zircon’s color ranges from 6 to 7.5 on the Mohs scale of hardness and is often heat-treated to produce blue and colorless varieties, as well as orange, yellow, and red hues. This heat treatment can sometimes be reversible with prolonged exposure to bright light, causing the color to revert to a lighter shade. Tanzanite, with a hardness of 6 to 7 on the Mohs scale, is also susceptible to damage from high temperatures and sudden temperature changes.
Blue topaz, while also considered a December birthstone, is a silicate mineral composed of aluminum and fluorine. It displays a glass-like luster and strong chemical bonding, making it relatively hard despite its cleavage. Blue topaz varieties include London Blue (deep inky blue), Swiss Blue (vibrant medium light blue), and Sky Blue (light aqua). Most commercially available blue topaz is created by irradiating naturally colorless topaz. Its chemical formula is Al2SiO4(F,OH)4.
The following table summarizes the hardness of the December birthstones:
| Gemstone | Mohs Hardness |
|---|---|
| Zircon | 6 - 7.5 |
| Tanzanite | 6 - 7 |
| Turquoise | Not specified |
| Blue Topaz | Not specified |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been imbued with symbolic meaning. Turquoise was believed to guarantee health and good fortune, offering protection against accidents and disaster. The ancient Egyptians and Chinese highly valued it for its perceived beneficial powers. While the sources do not detail specific metaphysical beliefs associated with tanzanite and zircon, they highlight the historical belief in the protective qualities of gemstones in general.
Care and Cleaning
Proper care is essential to maintain the beauty of these December birthstones. Zircon should be handled with care, avoiding rough conditions like gardening or sports, as it tends to abrade. Cleaning can be done with a soft brush and mild soap in warm water; ultrasonic and steam cleaners are not recommended. Tanzanite should also be cleaned with warm, soapy water, avoiding ultrasonic and steam cleaners. It is best set in earrings or pendants to minimize wear, as it is prone to abrasion and can crack with sudden temperature changes. Turquoise care instructions are not provided in the sources. Blue topaz, while harder, is somewhat delicate due to its cleavage and should be handled with care.
Varieties of Blue Topaz
Within the realm of blue topaz, several distinct varieties are recognized. London Blue topaz is prized for its deep, inky blue color, while Swiss Blue topaz offers a vibrant, medium-light blue hue. Sky Blue topaz presents a lighter, aqua-like shade. Natural blue topaz, though rare, can sometimes be mistaken for aquamarine due to their similar color profiles.
Conclusion
December’s birthstones – turquoise, tanzanite, and zircon – represent a captivating blend of history, beauty, and symbolism. From the ancient protective powers attributed to turquoise to the modern allure of tanzanite and the vibrant hues of zircon, these gemstones offer a diverse range of options for those born in the final month of the year. Each stone’s unique geological origins and gemological properties contribute to its individual charm, making December a truly special month for gemstone enthusiasts.