December boasts a remarkable selection of birthstones, offering a spectrum of blue hues to suit every preference. While turquoise and lapis lazuli hold traditional significance, the modern December birthstones – blue topaz, blue zircon, and tanzanite – have gained prominence for their beauty, versatility, and captivating lore. This article delves into the origins, properties, and symbolism of these three gemstones, providing a comprehensive overview for enthusiasts and those seeking the perfect December adornment.
A History Rooted in Tradition and Modern Appeal
For centuries, December was associated with turquoise and lapis lazuli. However, the 20th century saw the addition of blue topaz, blue zircon, and tanzanite to the list of recognized December birthstones. This expansion reflects both evolving gemological preferences and the discovery of new and exciting gemstone sources. Victorians, in particular, displayed a fondness for blue zircon, with fine examples appearing in English estate jewelry from the 1880s. The name "topaz" itself originates from the Sanskrit word for "fire," hinting at the gem’s long-held appreciation. Turquoise, with a history stretching back millennia, was cherished by ancient Egyptians and Chinese artisans alike, believed to guarantee health and good fortune.
Geological Origins and Global Sources
The geological formation and sourcing of these three gemstones vary considerably. Turquoise, a semi-translucent to opaque gem, often displays veins of matrix – remnants of the rock in which it formed. Blue zircon is frequently found alongside sapphire deposits, with significant sources in Sri Lanka, Australia, Myanmar, Vietnam, and Cambodia. Elahera, a region in central Sri Lanka, is particularly renowned for its zircon production. Australia’s Harts Range also yields zircon in a range of colors, including yellow-brown, orangy brown, pink, and purple.
Blue topaz, while naturally occurring, is often created through irradiation of colorless topaz. The gem’s chemical composition, Al2SiO4(F,OH)4, features strong chemical bonding, contributing to its hardness.
Tanzanite, a relatively recent discovery, is found in a very limited geographical area – the Merelani Hills of northern Tanzania. This scarcity contributes to its value and desirability.
Gemological Properties: A Comparative Overview
Each of these December birthstones possesses unique gemological characteristics. Blue topaz is a silicate mineral with a glass-like luster and deep cleavage, making it somewhat delicate despite its hardness. Its color ranges from dark, inky blues (London Blue) to lighter, cooler shades (Swiss Blue and Sky Blue).
Zircon ranges from 6 to 7.5 on the Mohs scale of hardness. It is commonly heat-treated to produce blue and colorless varieties, as well as orange, yellow, and red hues. While generally stable, heat-treated zircon can sometimes revert to its original color with prolonged light exposure.
Tanzanite, with a hardness of 6 to 7 on the Mohs scale, is susceptible to cracking if exposed to sudden temperature changes. It is also affected by hydrochloric and hydrofluoric acids. Most tanzanite undergoes heat treatment to enhance its blue to violet hues, a process that does not compromise its durability.
The following table summarizes key gemological properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Luster | Color Range |
|---|---|---|---|---|
| Blue Topaz | Al2SiO4(F,OH)4 | 8 | Glass-like | Dark blue to light aqua |
| Blue Zircon | (ZrSiO4) | 6-7.5 | Adamantine | Blue, colorless, orange, yellow, red |
| Tanzanite | Ca2Al3(SiO4)3(OH) | 6-7 | Vitreous | Blue to violet |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been imbued with symbolic meaning. Turquoise, revered for millennia, was believed to possess protective powers, safeguarding wearers from falls and misfortune. Hindu mystics associated it with wealth after beholding the new moon.
While specific metaphysical beliefs surrounding blue topaz and blue zircon are less extensively documented in the provided sources, turquoise has a rich history of symbolism. Ancient Egyptians adorned themselves with turquoise, believing it offered protection and good fortune.
Care and Cleaning: Preserving December’s Brilliance
Proper care is essential to maintain the beauty of these December birthstones. Due to its cleavage, blue topaz requires careful handling to avoid damage. Zircon, prone to abrasion, should not be worn during rough activities. Ultrasonic and steam cleaners are not recommended for zircon or tanzanite.
Tanzanite, susceptible to cracking from temperature fluctuations, should be treated with extra caution. All three gemstones are best cleaned with a soft brush and mild soap in warm water. Exposure to harsh chemicals should be avoided. Zircon’s color can be altered by heat, so avoid prolonged exposure to high temperatures.
Varieties and Market Appeal
Blue topaz is available in several distinct varieties, each with its unique appeal. London Blue topaz, with its deep, inky hue, is highly prized by collectors. Swiss Blue topaz offers a vibrant, medium-light blue, while Sky Blue topaz presents a delicate, aqua-colored appearance.
Zircon exhibits a wide range of colors, making it a versatile choice for jewelry design. Tanzanite’s pleochroism – the ability to display different colors depending on the viewing angle – adds to its allure.
The market for these gemstones is influenced by factors such as color intensity, clarity, cut, and carat weight. Tanzanite, due to its limited source, often commands a higher price than blue topaz or zircon.
Conclusion
The December birthstones – blue topaz, blue zircon, and tanzanite – represent a captivating blend of history, geological wonder, and aesthetic beauty. From the ancient symbolism of turquoise to the modern appeal of tanzanite, these gemstones offer a diverse range of options for those born in the final month of the year. Understanding their unique properties and origins allows for informed selection and appreciation of these remarkable gifts from the earth.