December boasts a unique distinction among birthstone months: not one, but three official gemstones – tanzanite, turquoise, and zircon – each offering a captivating shade of blue and a rich history. These gemstones provide a diverse palette for those born in December, allowing for a personal connection based on aesthetic preference or symbolic resonance. This article delves into the geological origins, historical significance, and gemological properties of these three December birthstones, exploring their individual characteristics and shared association with the final month of the year.
History and Lore
The tradition of assigning gemstones to specific months dates back millennia, rooted in ancient biblical and cultural beliefs. While the modern list of birthstones has evolved, with adjustments made by organizations like the National Association of Jewelers and the Jewelry Industry Council of America, the association of gemstones with December has remained consistent, though expanded to include three distinct options.
Turquoise holds the longest history of human appreciation, with evidence of its use dating back nearly 6,000 years. Ancient Egyptians prized it for adornment, incorporating it into scarab amulets and royal regalia. Persian architects utilized turquoise powder in mosque domes, a testament to its enduring beauty. In the American Southwest, Navajo silversmiths revered it as “stone fallen from the sky,” believing it offered protection from thunder gods.
Zircon, while less prominently featured in ancient lore compared to turquoise, has been utilized in jewelry for over 2,000 years. Its versatility in color, particularly the popular blue variety, contributed to its widespread appeal.
Tanzanite is the most recent addition to the December birthstone family, discovered in northern Tanzania in 1967. The American Gem Trade Association (AGTA) officially recognized it as a December birthstone in 2002, marking the first change to the official list since 1912. Tiffany & Co. played a pivotal role in popularizing this gem, giving it the trade name “Tanzanite” and showcasing its unique violet-blue hues.
Geological Formation and Sources
Each of these December birthstones originates through distinct geological processes and is sourced from specific locations around the globe.
Turquoise forms through a chemical reaction between groundwater containing copper and bedrock minerals. This process creates an opaque stone exhibiting stunning shades of blue and green, often marked by dark lines and shapes known as matrix, derived from the surrounding rock.
Tanzanite, a blue-violet variety of the mineral zoisite, is exceptionally rare, found exclusively in the Merelani Hills of northern Tanzania. Its formation is linked to intense heat generated during the geological upheavals that created Mount Kilimanjaro approximately 585 million years ago, altering brown zoisite into the vibrant blue-violet hues characteristic of tanzanite.
Zircon, occurring in a wide range of colors, is found in various locations worldwide. The blue variety, particularly favored as a December birthstone, is often created through heat treatment of colorless zircon.
Gemological Properties
The three December birthstones exhibit unique gemological properties that contribute to their individual appeal.
Turquoise: This gem is semi-translucent to opaque, displaying colors ranging from blue to green. The presence of matrix adds to its character and authenticity.
Tanzanite: A remarkable gem, tanzanite displays trichroism, meaning it can exhibit three different colors – blue, violet, and burgundy – depending on the viewing angle and lighting conditions. Its rarity and pleochroism contribute to its value.
Zircon: Zircon is known for its brilliance and fire, often displaying a rainbow-like effect. While available in many colors, blue zircon is the most popular choice for December birthstone jewelry.
A comparative overview of key properties is presented below:
| Gemstone | Chemical Formula | Color | Transparency | Hardness (Mohs) |
|---|---|---|---|---|
| Turquoise | CuAl6(PO4)4(OH)8·4H2O | Blue to Green | Opaque | 5-6 |
| Tanzanite | Ca2Al3(SiO4)3(OH) | Blue-Violet | Transparent to Translucent | 6.5-7 |
| Zircon | ZrSiO4 | Blue (most common for December) | Transparent | 6.5-7.5 |
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 success, happiness, and prosperity. Ancient cultures believed it offered protection from harm, particularly during travel. It is thought to calm nerves and promote a sense of well-being. For those ruled by Jupiter, Pisces and Sagittarius, turquoise is believed to protect energy and provide safety on challenging paths.
Tanzanite is often linked to transformation and spiritual growth. Its vibrant color is said to stimulate intuition and enhance psychic abilities.
Zircon, particularly blue zircon, is believed to promote wisdom, honor, and prosperity. It is also associated with calming emotions and fostering a sense of inner peace.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these December birthstones.
Turquoise, being relatively soft (5-6 on the Mohs scale), is susceptible to scratches and damage from harsh chemicals. It should be cleaned with a soft cloth and mild soapy water. Avoid ultrasonic cleaners and harsh cleaning agents.
Tanzanite, with a hardness of 6.5-7, requires gentle handling. It can be cleaned with warm, soapy water and a soft brush. Avoid sudden temperature changes and exposure to strong chemicals.
Zircon, with a hardness of 6.5-7.5, is relatively durable but can still be chipped or scratched. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners can be used with caution.
Conclusion
The December birthstones – tanzanite, turquoise, and zircon – represent a captivating trio of blue hues, each with a unique history, geological origin, and symbolic meaning. From the ancient allure of turquoise to the modern discovery of tanzanite and the enduring brilliance of zircon, these gemstones offer a diverse range of options for those born in December. Their individual properties and associated beliefs contribute to their enduring appeal, making them cherished symbols of the season and meaningful gifts for those celebrating a December birthday.