December boasts a remarkable array of birthstones, offering a spectrum of blue hues to those born in the final month of the year. Unlike some months with a single, definitive gemstone, December presents a choice of four: turquoise, tanzanite, blue zircon, and blue topaz. Each possesses a unique history, geological origin, and set of gemological properties, contributing to their enduring appeal. This article will delve into the characteristics of each of these December birthstones, exploring their historical significance, physical attributes, and the symbolism associated with them.
A History of December’s Gemstones
The tradition of associating specific gemstones with each month of the year dates back centuries, with roots in ancient astrology and religious beliefs. While the modern list of birthstones has evolved over time, the December stones have enjoyed consistent recognition for their beauty and perceived powers. Turquoise, with a history stretching back millennia, was revered by ancient civilizations. As early as 3,000 years ago, Chinese artisans carved turquoise, and the pharaohs of Egypt adorned themselves with it, believing it to possess protective qualities and guarantee good health and fortune. From the 13th century onward, it was thought to safeguard against falls, even breaking into pieces to warn of impending disaster. Hindu mystics associated turquoise with wealth after observing the new moon.
The other December birthstones – blue zircon, blue topaz, and tanzanite – gained prominence more recently. Blue zircon, in particular, has a long history, though its color variations have shifted in popularity over time. Tanzanite is the newest addition to the December birthstone family, discovered in Tanzania in the 1960s and quickly gaining favor for its vibrant color. Blue topaz, often produced through irradiation, has become a widely accessible and popular choice.
Geological Formation and Sources
Each of these gemstones originates through distinct geological processes and is found in specific locations around the globe. Turquoise is a secondary mineral, forming from hydrated copper aluminum phosphate, typically in arid regions. It often occurs in association with copper deposits, and its characteristic veins of matrix – remnants of the host rock – are considered desirable by many.
Blue topaz forms in igneous rocks and is found in various locations, including Brazil, Nigeria, and Russia. The blue color seen in most commercially available blue topaz is achieved through irradiation of naturally colorless topaz.
Zircon is a zirconium silicate mineral (ZrSiO4) found in metamorphic and igneous rocks. Blue zircon’s color is typically achieved through heat treatment. Sources include Cambodia, Sri Lanka, and Myanmar. The quality of zircon is categorized as “low” or “high,” with “high zircon” being the more desirable form found in jewelry.
Tanzanite, a relatively recent discovery, is found exclusively in the Merelani Hills of northern Tanzania. It is a trichroic gemstone, meaning it exhibits three different colors depending on the viewing angle – blue, violet, and burgundy. This unique property contributes to its allure.
Gemological Properties
The four December birthstones exhibit a range of gemological properties that contribute to their individual characteristics and suitability for jewelry.
Turquoise: A semi-translucent to opaque gem, turquoise’s color ranges from blue to green. Its quality is graded on color, matrix, and texture, with dense textures exhibiting better polish luster. The most valuable color is a bright “robin’s egg” blue with even distribution.
Blue Topaz: A silicate mineral composed of aluminum and fluorine, blue topaz possesses a glass-like luster and deep cleavage. It ranges in color from dark inky blues (London Blue) to lighter shades (Swiss Blue and Sky Blue). Its chemical formula is Al2SiO4(F,OH)4.
Blue Zircon: Zircon exhibits a wide range of colors, but blue is the most popular. The blue color is usually greenish and almost always heat-treated. Radioactive elements within zircon can cause changes to its crystalline structure over time.
Tanzanite: Tanzanite is known for its trichroism, displaying blue, violet, and burgundy hues. The most valuable colors are vibrant pure blue, bright purplish-blue, and violet-blue.
The following table summarizes key properties:
| Gemstone | Chemical Formula | Color Range | Hardness (Mohs) | Luster |
|---|---|---|---|---|
| Turquoise | CuAl6(PO4)4(OH)8·4H2O | Blue to Green | 5-6 | Waxy to Vitreous |
| Blue Topaz | Al2SiO4(F,OH)4 | Dark Blue to Light Blue | 8 | Vitreous |
| Blue Zircon | ZrSiO4 | Blue (often greenish), Brown, Red, Yellow | 6.5-7.5 | Adamantine |
| Tanzanite | Ca2Al3(SiO4)3(OH) | Blue, Violet, Burgundy | 6-7 | Vitreous |
Symbolism and Metaphysical Beliefs
Throughout history, each of these gemstones has been attributed with various symbolic meanings and metaphysical properties. Turquoise has long been associated with protection, good fortune, and health. Ancient cultures believed it could ward off evil and safeguard travelers.
Blue topaz is often associated with communication, loyalty, and clarity of thought. It is believed to promote honesty and openness.
Blue zircon is thought to enhance wisdom, prosperity, and honor. It is also believed to promote restful sleep and protect against negative energy.
Tanzanite is considered a stone of transformation, promoting spiritual growth and intuition. It is believed to facilitate communication with the higher self and encourage positive change.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these December birthstones. Turquoise, being relatively soft, is susceptible to scratches and should be protected from harsh chemicals and impacts. Cleaning can be done with a soft cloth and mild soapy water.
Blue topaz, with its good hardness, is relatively durable but can be chipped with a sharp blow. It can be cleaned with warm soapy water and a soft brush.
Blue zircon, while reasonably hard, possesses deep cleavage planes, making it prone to chipping. Gentle cleaning with mild soap and water is recommended.
Tanzanite is also susceptible to damage from heat and chemicals. Cleaning should be done with warm soapy water and a soft brush, and ultrasonic cleaners should be avoided.
Conclusion
The December birthstones – turquoise, tanzanite, blue zircon, and blue topaz – represent a diverse and captivating collection of gemstones. Each stone carries a unique history, geological origin, and set of gemological properties, offering a wide range of choices for those born in December. From the ancient protective powers of turquoise to the modern allure of tanzanite, these gemstones continue to fascinate and inspire, embodying the beauty and mystery of the natural world.