The month of December is uniquely distinguished in the world of gemology, holding the distinction of having the most birthstones of any month. While many months are assigned a single gem, December is associated with four officially recognized birthstones, all united by their captivating blue hues that evoke the cool, serene, and sometimes mysterious palette of winter. These stones—turquoise, tanzanite, zircon, and blue topaz—offer a remarkable diversity in terms of history, origin, and gemological character. For individuals born on December 12th, or any day in the month, this abundance provides a wide array of choices, each gemstone carrying its own story, symbolism, and practical considerations for jewelry. This article provides a detailed exploration of each of these four December birthstones, examining their historical significance, geological origins, gemological properties, cultural symbolism, and care requirements, drawing exclusively from authoritative sources to present an expert and comprehensive guide.
Historical and Cultural Significance
The tradition of associating specific gemstones with months of the year has deep historical roots, often tracing back to ancient religious and cultural practices. The earliest known reference to a system of birthstones is found in the biblical account of the High Priest’s Breastplate of Aaron, which featured twelve gemstones corresponding to the twelve tribes of Israel. Over centuries, this concept evolved, with various cultures developing their own lists of mystical stones. The modern standardized list of birthstones was largely shaped in the early 20th century. In 1912, the National Association of Jewelers in the United States established an official list, which has been updated several times to reflect new gemstone discoveries and commercial availability.
The addition of multiple birthstones for December is a relatively modern development, believed to offer consumers a greater variety of colors and price points. The evolution of December’s birthstone list is a clear example of this process. Initially, turquoise was the primary gem associated with the month. In 1952, the Jewelry Industry Council of America updated the list to include zircon. Later, in 2002, tanzanite was added, recognizing the gem’s rising popularity and unique story. Blue topaz, while not always listed as an official birthstone in all historical lists, has become a prominent and beloved choice for December, especially in the United States, where it is the official state gem of Texas. This sequence of additions—turquoise (ancient), zircon (1952), tanzanite (2002), and blue topaz (modern commercial prominence)—illustrates how the birthstone tradition is not static but adapts to include new and significant gemstones.
Turquoise: The Ancient Sky Stone
Turquoise is arguably the most historically significant of the December birthstones, with a legacy that spans millennia and continents. Its name itself tells a story of trade and travel; the gem was found in Persia (modern-day Iran) and along the Sinai Peninsula, and it reached European markets through trade routes that passed through Turkey, leading to its name, derived from the French pierre turquoise, meaning "Turkish stone."
Historical Lore and Symbolism
From antiquity, turquoise has been revered as a talisman of protection and good fortune. Its relative softness and ease of carving made it a favored material for amulets and inscribed ornaments. Ancient cultures believed it could warn the wearer of approaching danger or illness by changing color, often becoming pale. This protective quality was especially prized by lovers and married couples, who saw it as a guardian of relationships and a preserver of friendship when given as a gift.
Different cultures imbued turquoise with their own unique meanings: * Tibetan Culture: Turquoise was considered a stone of fortune, health, and success. It was so highly valued that it was often used as a form of currency. * Ancient Americas: Both the Incas and the Mayas offered turquoise as a gift to their gods. For the Native American tribes of the Southwestern United States, the gemstone is deeply connected to the earth and sky, symbolizing youth, strength, and spiritual grounding. * Modern Symbolism: Today, turquoise is widely associated with protection, grounding, and a sense of calm, making it a popular choice for those seeking stability in a chaotic world.
Geological Formation and Sources
Turquoise is a hydrated phosphate of copper and aluminum, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. Its characteristic blue-to-green-blue color comes from copper, while iron impurities can shift the hue toward green. It forms in arid regions where acidic, copper-rich water percolates through aluminum-bearing rocks, depositing the mineral in nodules or veins. Major historical and modern sources include Iran (known for its intense, uniform "robin's egg blue"), the United States (particularly Arizona, Nevada, and New Mexico), and China. The material from the American Southwest is renowned for its distinctive matrix patterns, where the host rock is incorporated into the gem.
Gemological Properties
Turquoise is a relatively soft and porous gemstone, which affects its durability and care. It typically ranges from 5 to 6 on the Mohs hardness scale, making it susceptible to scratching and damage. Its transparency is usually opaque to semi-translucent. Because natural turquoise can vary greatly in hardness and color, much of the commercial turquoise is stabilized—treated with a clear resin or wax to harden the material and enhance its color. Some turquoise is also dyed to achieve a more uniform blue hue.
Key Properties of Turquoise: * Chemical Composition: CuAl₆(PO₄)₄(OH)₈·4H₂O * Color: Blue to green-blue * Hardness (Mohs): 5–6 * Transparency: Opaque to semi-translucent * Origin: Iran, USA (Arizona, Nevada, New Mexico), China * Special Properties: Often stabilized or dyed for commercial use
Care and Cleaning
Due to its porosity and softness, turquoise requires careful handling. It should not be exposed to chemicals, cosmetics, perfumes, or harsh cleaning agents, as these can damage or discolor the stone. Cleaning should be done with a soft, dry cloth. For jewelry set with turquoise, it is best to remove it before activities that could cause impact or exposure to substances, such as swimming, gardening, or applying lotions. Stabilized turquoise is more durable but still requires gentle care.
Tanzanite: The Modern Marvel
Tanzanite is the newest of the December birthstones, a gem of extraordinary beauty and rarity that has captured the imagination of the gemological world in a very short time. Its story is a testament to the potential for new discoveries in our modern era.
Historical Lore and Symbolism
Tanzanite’s history is remarkably brief. It was first identified in the 1960s in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The gem was initially misidentified as a different mineral but was later recognized as a variety of the mineral zoisite. Its rapid rise to prominence is largely credited to the jewelry company Tiffany & Co., which launched a marketing campaign in 1968, famously dubbing it "the most beautiful blue gemstone discovered in 2,000 years." Its name, tanzanite, was bestowed in honor of its exclusive origin country.
As a modern gem, tanzanite lacks the ancient legends of turquoise. However, it has quickly developed its own symbolism, often linked to themes of transformation, new beginnings, and spiritual awakening. Its unique color shift is seen as a metaphor for the ability to see different perspectives and embrace change. It is associated with clarity, intuition, and a sense of purpose.
Geological Formation and Sources
Tanzanite is a variety of the mineral zoisite, with the chemical formula Ca₂Al₃(SiO₄)₃(OH). Its stunning violet-blue to purplish-blue color is the result of trace amounts of vanadium within its crystal structure. A defining characteristic of tanzanite is its trichroism, meaning it displays three different colors—typically blue, violet, and red-brown—from different crystal directions. This phenomenon is responsible for its captivating color play.
Geologically, tanzanite is found only in a single, small area in Tanzania, covering just a few square kilometers. This extreme rarity is a key factor in its value and allure. The gem is formed through a unique geological process involving intense heat and pressure from tectonic activity in the East African Rift, which altered the original zoisite crystals. The vast majority of tanzanite on the market has been heat-treated to enhance its blue coloration, a stable and permanent process that is standard in the trade.
Gemological Properties
Tanzanite is a relatively soft gemstone, with a Mohs hardness of 6 to 6.5, making it less suitable for rings worn daily unless protected by a bezel setting. It is transparent to translucent and is prized for its deep, saturated color. Its value is influenced by color, with the most prized stones showing a rich, even blue-violet hue without overly strong brownish tints.
Key Properties of Tanzanite: * Chemical Composition: Ca₂Al₃(SiO₄)₃(OH) (a variety of zoisite) * Color: Violet-blue to purplish-blue * Hardness (Mohs): 6–6.5 * Transparency: Transparent to translucent * Origin: Tanzania (Merelani Hills) * Special Properties: Trichroic (displays three colors); typically heat-treated
Care and Cleaning
Tanzanite’s relative softness and cleavage (a tendency to split along certain planes) require careful handling. It is not recommended for rings or bracelets that are subject to daily wear and tear. The best settings are pendants or earrings. To clean tanzanite, use warm, soapy water and a soft brush, avoiding ultrasonic and steam cleaners, which can cause fractures. Store tanzanite jewelry separately to prevent scratching by harder gems.
Zircon: The Fire and Brilliance
Zircon is one of the oldest minerals on Earth, with crystals dating back billions of years. Despite its name, it is not related to the synthetic material cubic zirconia. Blue zircon, in particular, has become a popular and durable alternative for December.
Historical Lore and Symbolism
Zircon has a long history, though its blue variety is a more modern development. Historically, zircon was valued for its brilliance and fire, often used as a diamond simulant. The blue color in zircon is typically achieved through heat treatment of brown or yellow zircon, a process that can produce a wide range of blue shades, from light to intense.
In terms of symbolism, zircon is associated with clarity, wisdom, and honor. It is believed to promote mental clarity and focus, helping the wearer to see the truth and make wise decisions. Its strong dispersion (fire) is seen as a metaphor for inner light and enlightenment. As a birthstone, it offers a durable and brilliant blue option for December.
Geological Formation and Sources
Zircon is a zirconium silicate, with the chemical formula ZrSiO₄. It forms in a variety of geological environments, most commonly in igneous and metamorphic rocks. The blue variety is primarily sourced from Australia, Thailand, and Cambodia. Australian zircon is particularly known for its high-quality blue stones. The heat treatment process to produce blue zircon is stable and permanent, and it is a standard industry practice.
Gemological Properties
Zircon is one of the hardest of the December birthstones, with a Mohs hardness of 6.5 to 7.5, making it quite durable for jewelry. It is transparent to translucent and is renowned for its exceptional brilliance and fire, which often surpasses that of diamond. Blue zircon can range from a light, sky blue to a deep, vivid blue, depending on the treatment and the original color of the rough material.
Key Properties of Zircon: * Chemical Composition: ZrSiO₄ * Color: Blue, yellow, brown, red (blue is typically heat-treated) * Hardness (Mohs): 6.5–7.5 * Transparency: Transparent to translucent * Origin: Australia, Thailand, Cambodia * Special Properties: Strong dispersion (fire); anisotropic (double refraction)
Care and Cleaning
With a hardness of 6.5 to 7.5, zircon is suitable for most types of jewelry, including rings. However, it can be brittle and may cleave if struck with force. It is best to avoid ultrasonic cleaners and steam cleaners, as sudden temperature changes can cause fractures. Cleaning should be done with warm, soapy water and a soft brush. Store zircon pieces separately to prevent scratching other jewelry.
Blue Topaz: The Durable Winter Blue
Blue topaz is the hardest and most durable of the December birthstones, offering a brilliant, clear blue that is both affordable and resilient. Its journey to becoming a December staple is a story of modern gemstone treatment and market demand.
Historical Lore and Symbolism
The exact historical origin of blue topaz is unclear, as the gem has been found throughout history. However, the bright, saturated blue topaz known today is almost always the result of modern treatment processes. Topaz in its natural state is most commonly colorless or pale yellow, but it can be treated with irradiation and heat to produce the vibrant blues that are popular in jewelry.
As a modern birthstone, blue topaz is associated with clarity, communication, and calm. Its clear, icy blue color is reminiscent of winter skies and frozen lakes, making it a perfect seasonal gem. It is valued for its durability and brilliance, symbolizing purity and truth.
Geological Formation and Sources
Topaz is a silicate mineral with the chemical formula Al₂SiO₆. It forms in igneous rocks, particularly in silica-rich magmas. Natural blue topaz is exceptionally rare; the vast majority of blue topaz on the market is created by treating colorless or pale topaz with irradiation, followed by heat treatment to achieve the desired blue color. This process is stable and permanent.
Blue topaz is mined in several countries, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States. The United States, particularly Colorado, is a well-known source of high-quality topaz, though Brazil and Myanmar also produce significant quantities. It is the official state gem of Texas, a testament to its popularity in the U.S.
Gemological Properties
Blue topaz is the hardest December birthstone, with a Mohs hardness of 8. This makes it highly durable and resistant to scratches, making it an excellent choice for everyday wear, including rings and bracelets. It is transparent and has a brilliant, vitreous luster. The color can range from a light sky blue to a deep cobalt blue, depending on the intensity of the treatment.
Key Properties of Blue Topaz: * Chemical Composition: Al₂SiO₆ * Color: Sky blue to cobalt blue (typically irradiated/heat-treated) * Hardness (Mohs): 8 * Transparency: Transparent * Origin: USA, Brazil, Sri Lanka, Mexico, Nigeria * Special Properties: Typically irradiated/heat-treated; very durable
Care and Cleaning
Blue topaz is very durable and easy to care for. Its hardness of 8 makes it resistant to everyday wear. It can be cleaned safely with warm, soapy water and a soft brush. While it is generally resistant to chemicals, it is still advisable to avoid prolonged exposure to harsh chemicals and extreme temperatures. Ultrasonic and steam cleaners are usually safe for blue topaz, but it is always best to check with a jeweler first, especially if the stone is set in a delicate piece or with other gems.
Comparative Gemological Properties
To better understand the practical differences between these four December birthstones, a comparison of their key gemological properties is invaluable. The following table summarizes the information detailed in the individual sections, providing a clear overview for enthusiasts and buyers.
| Gemstone | Chemical Composition | Color | Hardness (Mohs) | Transparency | Origin | Special Properties |
|---|---|---|---|---|---|---|
| Turquoise | CuAl₆(PO₄)₄(OH)₈·4H₂O | Blue to green-blue | 5–6 | Opaque to semi-translucent | Iran, USA | Stabilized/dyed often |
| Tanzanite | Ca₂Al₃(SiO₄)₃(OH) | Violet-blue to purplish-blue | 6–6.5 | Transparent to translucent | Tanzania | Trichroic, heat-treated |
| Zircon | ZrSiO₄ | Blue, yellow, brown, red | 6.5–7.5 | Transparent to translucent | Australia, Thailand | Strong dispersion, anisotropic |
| Blue Topaz | Al₂SiO₆ | Sky blue to cobalt blue | 8 | Transparent | USA, Brazil | Irradiated/heat-treated |
This table highlights the significant range in durability among the four stones, from the relatively soft turquoise to the hard and durable blue topaz. It also shows the variety in color origins, from the natural copper-induced blue of turquoise to the treated blues of zircon and topaz and the unique vanadium-induced color of tanzanite.
Choosing Your December Birthstone
With four distinct options, selecting a December birthstone is a matter of personal preference, lifestyle, and what the individual values most in a gemstone.
- For the History and Culture Lover: Turquoise is the clear choice. Its ancient legacy, spanning from Persian kings to Native American warriors, offers a deep connection to human history and spirituality.
- For the Seeker of Rarity and Modernity: Tanzanite is unparalleled. Its exclusive origin in a single location in Tanzania and its recent discovery make it a gem of the modern era, perfect for someone who values uniqueness and a contemporary story.
- For the Brilliant and Durable Choice: Zircon offers the best of both worlds. It provides exceptional brilliance and fire, rivaling that of a diamond, combined with good durability (hardness of 6.5-7.5), making it suitable for a variety of jewelry settings.
- For Everyday Wear and Affordability: Blue Topaz is the most practical option. Its high hardness (8) ensures it can withstand daily wear, and its treated nature makes it widely available and more affordable than the other gems, offering a beautiful, clear blue without a high price tag.
Each of these gems shares the blue hue that defines December, but their individual characteristics ensure there is a perfect birthstone for every personality and preference within the month.
Conclusion
The four birthstones of December—turquoise, tanzanite, zircon, and blue topaz—represent a fascinating intersection of history, geology, and culture. From the ancient, protective talisman of turquoise to the modern, rare marvel of tanzanite; from the brilliantly fiery zircon to the durable, clear blue of topaz, each gem offers a unique narrative. Their collective blue palette provides a beautiful and meaningful connection to the winter season, reflecting its icy beauty and serene depth. For those born in December, this abundance of choice allows for a personal connection to a gemstone that not only adorns but also tells a story—of earth’s history, human belief, and the enduring allure of the natural world. Understanding their distinct properties, origins, and care requirements empowers enthusiasts and buyers to make an informed and cherished selection.