December boasts a unique distinction among the months: it has not one, but three recognized birthstones – Tanzanite, Zircon, and Turquoise. This selection reflects both historical traditions and more recent additions to the established birthstone lists. The American Gem Society has played a key role in defining and updating these lists, beginning with an initial publication in 1912, and continuing with additions in 1952, 2002, and 2016. This article will explore the history, geological origins, gemological properties, and symbolism associated with each of these December birthstones, drawing upon established gemological resources.
A History of December’s Gems
The concept of birthstones dates back to antiquity, originating with the twelve gems adorning the breastplate of Aaron, the high priest in the biblical Book of Exodus. These gems were initially associated with the zodiac signs, a tradition that evolved over time. By 1752, a connection between gems and months of the year began to emerge. Initially, classifications were based on color, but the discovery of new gemstones prompted revisions, leading to the official list published by the American Gem Society in 1912.
Throughout history, wearing gemstones was believed to bestow blessings, promote health, and offer protection. During the Middle Ages, it was thought that a gem’s power was amplified during its corresponding month. Today, selecting a birthstone remains a meaningful way to celebrate a birthday and connect with ancestral beliefs. The choice between Tanzanite, Zircon, and Turquoise offers a range of options, reflecting personal preference and symbolic resonance.
Tanzanite: A Modern Addition
Tanzanite is the newest addition to the December birthstone family, officially recognized in 2002. This relatively recent discovery has quickly gained popularity for its striking violet-blue hues. The gem is named after Tanzania, the East African country where it is exclusively found. Its limited geographical origin contributes to its value and desirability.
Zircon: A Long-Standing Tradition
Zircon has a much longer history as a December birthstone, appearing on birthstone lists as early as the initial American Gem Society publication in 1912. Historically, zircon was often confused with other gemstones, particularly diamonds, due to its brilliance and high refractive index. It comes in a variety of colors, including blue, red, yellow, and green, though blue zircon is the most commonly associated with December.
Turquoise: A Stone of Antiquity
Turquoise holds the longest-standing tradition as a December birthstone, and is listed as a traditional stone. Its use dates back thousands of years, with evidence of its adornment in ancient Egyptian tombs and by pre-Columbian civilizations in the Americas. The name "turquoise" originates from the French phrase "pierre turquoise," meaning "Turkish stone," as the gem was often imported to Europe through Turkey.
Geological Formation and Sources
Each of these December birthstones originates through distinct geological processes and is sourced from specific locations around the globe.
Tanzanite is formed through complex geological activity in the Merelani Hills of northern Tanzania. It is a variety of the mineral zoisite, and its unique color is attributed to the presence of vanadium. The gem forms in metamorphic rocks, created by intense heat and pressure. Tanzania remains the sole commercial source of tanzanite.
Zircon forms in igneous rocks, metamorphic rocks, and sedimentary deposits. It is a zirconium silicate mineral and can be found in various locations worldwide, including Cambodia, Sri Lanka, Myanmar, and Australia. Blue zircon is often created through heat treatment of naturally occurring brown zircon.
Turquoise is a hydrated phosphate of copper and aluminum, typically forming in arid regions through the interaction of copper-rich groundwater with volcanic rock. Significant sources of turquoise include Iran, Egypt, the United States (particularly Arizona and Nevada), and China. The color of turquoise varies depending on the presence of other minerals, such as iron and chromium.
Gemological Properties
Understanding the gemological properties of each birthstone is crucial for appreciation and proper care.
| Property | Tanzanite | Zircon | Turquoise |
|---|---|---|---|
| Chemical Formula | Ca2Al3(SiO4)3(V) | ZrSiO4 | CuAl6(PO4)4(OH)8·4H2O |
| Color | Violet-blue | Blue, Red, Yellow, Green | Blue-Green |
| Hardness (Mohs) | 6.5 - 7 | 6.5 - 7.5 | 5 - 6 |
| Refractive Index | 1.619 - 1.662 | 1.810 - 2.024 | 1.61 - 1.62 |
| Crystal System | Triclinic | Tetragonal | Triclinic |
Tanzanite exhibits strong trichroism, meaning it displays three different colors (blue, violet, and burgundy) depending on the viewing angle. Zircon’s high refractive index contributes to its brilliance and fire. Turquoise is a relatively soft stone, making it susceptible to scratching and damage.
Symbolism and Metaphysical Beliefs
Throughout history, each of these gemstones has been attributed with various symbolic meanings and metaphysical properties.
Tanzanite is often associated with transformation, intuition, and spiritual awareness. It is believed to stimulate creativity and promote a sense of calm.
Zircon has been historically linked to prosperity, wisdom, and honor. Blue zircon, in particular, is thought to promote restful sleep and ward off nightmares.
Turquoise has long been considered a sacred stone, representing protection, healing, and good fortune. It is believed to strengthen the immune system, enhance communication, and promote emotional balance. In some cultures, turquoise is seen as a symbol of friendship and loyalty.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these December birthstones.
Tanzanite is relatively delicate and should be protected from harsh chemicals, extreme temperatures, and ultrasonic cleaners. Cleaning can be done with warm, soapy water and a soft brush.
Zircon is also susceptible to damage from heat and chemicals. It should be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners, as they can damage the stone.
Turquoise requires gentle care due to its softness. Avoid harsh chemicals, ultrasonic cleaners, and abrasive materials. Cleaning can be done with a soft cloth and mild soapy water. It is advisable to remove turquoise jewelry before engaging in strenuous activities.
Conclusion
December’s birthstones – Tanzanite, Zircon, and Turquoise – offer a diverse range of colors, histories, and symbolic meanings. From the modern allure of Tanzanite to the ancient traditions surrounding Turquoise and the long-standing presence of Zircon, each gem holds a unique appeal. The American Gem Society’s role in defining and updating birthstone lists ensures that these gems continue to be celebrated for their beauty and significance. Whether chosen for personal resonance, aesthetic preference, or historical connection, these December birthstones represent a timeless treasure.