December boasts a remarkable selection of birthstones – turquoise, tanzanite, and zircon – each offering a unique shade of blue and a rich history. These gems have captivated cultures for millennia, prized for their beauty, perceived protective qualities, and diverse origins. This article will delve into the geological properties, historical significance, and care of these three December birthstones, providing a comprehensive overview for enthusiasts and those seeking to understand their allure.
History and Lore
The history of these December birthstones spans continents and centuries. Turquoise, perhaps the oldest of the three, has been cherished since ancient times. Evidence suggests its use by pharaohs and rulers in ancient Egypt, and it was skillfully carved by Chinese artisans over 3,000 years ago. Beyond its aesthetic appeal, turquoise was believed to possess potent protective powers. From the 13th century onward, it was thought to safeguard wearers from falls, particularly from horseback, and even to warn of impending disaster by fracturing. In Hindu mysticism, viewing turquoise after a new moon was believed to bring exceptional wealth.
Zircon’s history is equally intriguing, with the origin of its name debated between Arabic and Persian roots, reflecting its varied color palette – red, orange, yellow, brown, green, and blue. During the Middle Ages, zircon was associated with inducing sleep and warding off evil spirits. Within the Hindu tradition, it alternates with hessonite garnet as one of the nine gems of the navaratna, believed to bestow wealth, wisdom, and good health upon the wearer. Victorian-era jewelry frequently featured blue zircon, demonstrating its popularity in the 19th century.
Tanzanite, the newest addition to the December birthstone family, lacks the extensive historical background of turquoise and zircon. Its discovery is relatively recent, and its rise to prominence is a story of modern gemological appreciation.
Geological Formation and Sources
Turquoise is a semi-translucent to opaque gem, a copper aluminum phosphate, formed in semi-humid and dry environments where rock is present. It originates from chemicals seeping through rocks via rainwater and groundwater. The distinctive blue hue is attributed to the presence of copper, while iron contributes to green shades. The veined appearance, often featuring black, silver, tan, or gold, is due to remnants of the host rock.
Zircon, with a chemical formula of Al2SiO4(F,OH)4, is a silicate mineral known for its hardness and strong chemical bonding. It occurs in a wide range of colors, and colorless zircon is particularly prized for its brilliance and “fire,” often mistaken for diamond. Zircon is frequently found near sapphire deposits, with notable sources including Sri Lanka, Australia, Myanmar, Vietnam, and Cambodia.
Tanzanite’s formation is unique, originating as brownish zoisite that undergoes heat treatment to reveal its characteristic blue to violet hues. The sources for these gems are not detailed in the provided materials.
Gemological Properties
Turquoise ranges from blue to green in color and is typically opaque. Its composition is copper aluminum phosphate.
Zircon exhibits a Mohs hardness of 6 to 7.5, making it relatively durable. It is commonly heat-treated to produce blue and colorless varieties, as well as orange, yellow, and red hues. While generally stable, some heat-treated zircon may revert to its original color with prolonged light exposure.
Tanzanite falls within a hardness range of 6 to 7 on the Mohs scale. It is susceptible to cracking under high temperatures or sudden temperature changes and can be affected by hydrochloric and hydrofluoric acids. The blue to violet color is achieved through heat treatment, a process that results in a permanent color change without compromising durability.
The following table summarizes the key gemological properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Color | Transparency |
|---|---|---|---|---|
| Turquoise | Copper Aluminum Phosphate | Not specified | Blue to Green | Opaque |
| Zircon | Al2SiO4(F,OH)4 | 6 – 7.5 | Red, Orange, Yellow, Brown, Green, Blue | Transparent to Opaque |
| Tanzanite | Not specified | 6 – 7 | Blue to Violet | Transparent |
Symbolism and Metaphysical Beliefs
Throughout history, these December birthstones have been imbued with symbolic meaning. Turquoise, beyond its protective qualities, was believed to guarantee health and good fortune. Zircon, in Hindu tradition, represents wealth, wisdom, and good health when included in the navaratna. While the provided sources do not detail specific metaphysical beliefs associated with tanzanite, its vibrant color and relative rarity likely contribute to its perceived value and desirability.
Care and Cleaning
Proper care is essential to maintain the beauty of these December birthstones. Tanzanite, due to its sensitivity to heat and chemicals, requires gentle cleaning with warm, soapy water. Ultrasonic and steam cleaners are not recommended. Zircon should also be cleaned with a soft brush and mild soap in warm water, avoiding ultrasonic and steam cleaners. Zircon is best avoided in rough conditions to prevent abrasion. Turquoise cleaning methods are not specified in the provided sources.
Conclusion
The December birthstones – turquoise, tanzanite, and zircon – represent a captivating blend of history, geological wonder, and symbolic meaning. From the ancient protective powers attributed to turquoise to the modern brilliance of tanzanite and the varied hues of zircon, these gems offer a diverse range of options for those born in the final month of the year. Understanding their unique properties and proper care ensures that these beautiful stones will continue to be cherished for generations to come.