December boasts a unique distinction among birthstone months: it has not one, but three associated gemstones – Tanzanite, Zircon, and Turquoise. These stones, while differing in origin and composition, share a common thread of captivating blue hues, making them a fitting representation for the winter month. This article will delve into the history, geological origins, gemological properties, and symbolism of each of these December birthstones, providing a comprehensive overview for enthusiasts and those seeking to understand the significance of these beautiful gems.
A History of December’s Gemstones
The formalization of modern birthstone lists occurred in 1912 by the Jewelers of America Association, now known as Jewelers of America, and has become widely accepted globally. However, the association of gemstones with specific months dates back much further, rooted in ancient traditions and beliefs. While the historical origins of assigning specific stones to December are less documented than for some other months, the individual histories of Tanzanite, Zircon, and Turquoise are rich and varied.
Turquoise, with its long history of use in jewelry and adornment, has been prized for millennia. Zircon, while often confused with cubic zirconia, has a history stretching back to the Middle Ages, and was valued for its brilliance. Tanzanite is the newest addition to the birthstone family, discovered relatively recently in 1967. Its rapid rise in popularity speaks to its exceptional beauty and rarity.
Tanzanite: A Recent Discovery
Tanzanite, a variety of the mineral zoisite, is a relatively recent addition to the world of gemstones. Discovered in 1967 in the Merelani Hills of Tanzania, its captivating blue and purple hues quickly garnered attention. The name “Tanzanite” was given by Tiffany & Co., recognizing its origin and unique color. The gem is a 24th-year wedding anniversary gemstone, signifying enduring love and commitment.
Demand for Tanzanite continues to exceed supply, contributing to its value and desirability. The most sought-after color is a deep blue with a purple shimmer, showcasing the gem’s trichroism – the ability to display different colors depending on the viewing angle.
Zircon: A Stone of Many Colors
Zircon is often mistakenly identified as cubic zirconia, a synthetic diamond simulant. However, natural zircon is a distinct gemstone with a long and fascinating history. While it can occur in a variety of colors, the blue varieties are most commonly associated with December. Zircon has been found in Sri Lanka, Myanmar, Tanzania, Brazil, Zimbabwe, and Madagascar.
Turquoise: A Stone of Protection and Healing
Turquoise, a vibrant blue-to-green mineral, has been revered for centuries by cultures around the world. It is not found within the Earth like most gemstones, but rather forms in the shells of mollusks in freshwater and marine environments. Turquoise is an 11th-year wedding anniversary gemstone, symbolizing a lasting and harmonious union.
Geological Formation and Sources
The geological formation of these three birthstones differs significantly. Tanzanite forms in metamorphic rocks within the Merelani Hills of Tanzania, a geographically limited source contributing to its rarity. Its formation involves complex geological processes involving heat and pressure.
Zircon, being a silicate mineral, forms in igneous rocks and metamorphic rocks. It is found in a wider range of locations, including Sri Lanka, Myanmar, Tanzania, Brazil, Zimbabwe, and Madagascar.
Turquoise, as a secondary mineral, forms through the chemical alteration of aluminum-rich rocks in arid regions. Significant sources include the southwestern United States, Iran, and China.
Gemological Properties
Each of these December birthstones possesses unique gemological properties that contribute to its beauty and value.
Tanzanite: A variety of zoisite, Tanzanite’s chemical formula is Ca2Al3(SiO4)3(OH). It exhibits strong pleochroism, displaying blue, violet, and burgundy hues depending on the viewing angle. Its hardness on the Mohs scale is 6.5 to 7.
Zircon: Zircon’s chemical formula is ZrSiO4. Blue zircon is often created through heat treatment of naturally occurring brown zircon. Its hardness ranges from 6.5 to 7.5 on the Mohs scale.
Turquoise: Turquoise is a hydrated copper aluminum phosphate with the chemical formula CuAl6(PO4)4(OH)8·4H2O. Its color is influenced by the presence of copper and iron. Turquoise is relatively soft, with a hardness of 5 to 6 on the Mohs scale.
The following table summarizes the key gemological properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Color(s) |
|---|---|---|---|
| Tanzanite | Ca2Al3(SiO4)3(OH) | 6.5 - 7 | Blue, violet, purple |
| Zircon | ZrSiO4 | 6.5 - 7.5 | Blue (often heat-treated), brown, clear |
| Turquoise | CuAl6(PO4)4(OH)8·4H2O | 5 - 6 | Blue-to-green |
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been imbued with symbolic meanings and metaphysical properties. While specific beliefs vary across cultures, certain themes consistently emerge.
Turquoise has long been considered a stone of protection, believed to ward off negative energy and bring good fortune. It is also associated with healing and spiritual growth.
Zircon, in some traditions, is believed to promote wisdom, honor, and prosperity. Blue zircon, in particular, is thought to calm the mind and enhance intuition.
Tanzanite, as a relatively new gemstone, has fewer established metaphysical beliefs. However, it is often associated with transformation, spiritual awareness, and communication.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these December birthstones.
Tanzanite, with its moderate hardness, is susceptible to scratches and chipping. It should be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and harsh chemicals.
Zircon, while relatively durable, can also be scratched. It should be cleaned similarly to Tanzanite, using warm, soapy water and a soft brush.
Turquoise, being the softest of the three, requires gentle handling. Avoid harsh chemicals, ultrasonic cleaners, and prolonged exposure to sunlight. It can be cleaned with a soft, damp cloth. Due to its porous nature, turquoise is often treated with wax or resin to enhance its durability and color.
Conclusion
December’s birthstones – Tanzanite, Zircon, and Turquoise – offer a diverse range of colors, histories, and symbolic meanings. From the recent discovery of Tanzanite in Tanzania to the ancient traditions surrounding Turquoise, each gemstone holds a unique place in the world of gemology. Whether chosen for their beauty, their historical significance, or their perceived metaphysical properties, these December birthstones continue to captivate and inspire. Their varied origins and properties make them a fascinating trio, representing the depth and complexity of the natural world.