The final month of the year is uniquely distinguished in the world of gemology by its trio of official birthstones: tanzanite, turquoise, and blue topaz. This rich association provides individuals born in December with a diverse palette of colors, ranging from the serene sky-blue of ancient lore to the deep, velvety indigo of a modern marvel and the crisp, icy brilliance of a classic favorite. Each of these gemstones carries its own distinct story, geological origin, and set of properties, making the December birthstone collection one of the most varied and fascinating in the entire calendar. This comprehensive guide delves into the science, history, and symbolism of these three remarkable gems, offering an in-depth exploration for gemstone enthusiasts, collectors, and anyone captivated by their beauty.
The journey through the December birthstones reveals a narrative that spans millennia and continents. Turquoise, one of the oldest known gemstones, has been treasured by civilizations across the globe for its protective qualities and vibrant hue. In contrast, tanzanite is a relative newcomer, discovered in the 20th century, yet it has rapidly ascended to become a celebrated and sought-after gem. Blue topaz, with its brilliant clarity and cool tones, bridges the ancient and the modern, offering a timeless elegance. Together, they represent a spectrum of blue that captures the essence of winter's chill and the festive sparkle of the holiday season. Understanding their individual characteristics is key to appreciating the full significance of this month's celebrated gems.
The Historical Significance and Lore of December's Gems
The history of the December birthstones is a tale of two ancient treasures and one modern sensation. Turquoise stands as the elder statesman of the group, with a legacy of use that stretches back for thousands of years. It has been found in ancient Egyptian tombs, worn by Persian rulers, and used extensively by the Indigenous peoples of the American Southwest. Its name is derived from the French phrase "pierre tourques," meaning "Turkish stone," a reference to the trade routes through which it traveled from Persia to Europe. For centuries, it was believed to be a stone of protection, warding off evil and bringing good fortune to the wearer. Its vibrant blue-green color, often marked with a distinctive matrix, made it instantly recognizable and highly prized.
Tanzanite's history is dramatically shorter, which adds to its mystique. This gemstone was not identified until the 1960s in the Merelani foothills of Mount Kilimanjaro in Tanzania. Its discovery is a modern-day gemological story, quickly capturing the attention of the jewelry world with its unique and captivating color. The Tiffany & Co. company recognized its potential and launched a major marketing campaign in 1968, cementing its status as a significant new gemstone. Its rapid rise from a geological curiosity to one of the most popular blue gemstones is a testament to its exceptional beauty.
Blue topaz, while not a December birthstone in its earliest assignments, has a long and storied history. It was often confused with other yellow or blue stones in antiquity. Its use in jewelry dates back to ancient Egypt, and it was believed in many cultures to have calming properties. The modern association of blue topaz with December, along with tanzanite and turquoise, was formalized by the American Gem Trade Association (AGTA) in 2002, when tanzanite was added to the official list. This update reflected the growing popularity of tanzanite and solidified the trio that is now synonymous with the month.
Geological Formation and Mining Locations
The origins of these three gemstones are as diverse as their appearances. Each forms under unique geological conditions, resulting in gems with distinct properties and availability.
Turquoise is a secondary mineral that forms when water containing minerals like copper and aluminum seeps through pre-existing rock. This process occurs in arid regions, where the evaporation of the water leaves behind deposits of the mineral in cracks and voids. The most famous and historically significant sources of turquoise are in Iran (Persia), which produces the prized "Persian blue" variety known for its uniform, sky-blue color with little to no matrix. Another major source is the Southwestern United States, particularly in states like Arizona, Nevada, and New Mexico, where turquoise is deeply intertwined with the culture and history of Native American tribes. The color of turquoise is directly influenced by its copper content (creating blue) and iron content (creating green), which explains its wide color range.
Tanzanite is a variety of the mineral zoisite and owes its existence to a unique and singular geological event. It is found in only one place on Earth: a small, four-square-kilometer mining area in the Merelani Hills of northern Tanzania. The gem formed around 585 million years ago when massive tectonic plate shifts and intense heat transformed the original zoisite crystals, introducing the elements (vanadium and chromium) responsible for its mesmerizing violet-blue hue. Its scarcity is a key factor in its value; the limited geographic source means that the world's supply is finite, making it a truly "one-generation" gemstone.
Blue topaz is a silicate mineral that forms in igneous rocks, specifically in pegmatites and hydrothermal veins. Unlike tanzanite, it is found in numerous locations around the world, including Brazil, Sri Lanka, Nigeria, and the United States. The natural color of topaz is typically colorless or pale yellow. The intense, deep blue of the varieties used in jewelry (such as London Blue Topaz) is almost always the result of treatment. Irradiation and heat are used to alter the crystal's structure and produce the desirable saturated blue color. This treatment is stable and permanent, making the beautiful blue topaz widely accessible and affordable.
Gemological Properties: A Scientific Perspective
Understanding the physical and chemical properties of a gemstone is crucial for appreciating its durability, appearance, and value. The December trio presents a fascinating study in contrasts, particularly concerning their hardness and stability.
| Gemstone | Mineral Family | Chemical Composition | Mohs Hardness | Crystal System | Typical Treatments |
|---|---|---|---|---|---|
| Turquoise | Phosphate | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | Triclinic | Stabilization, Waxing/Oiling |
| Tanzanite | Zoisite (Sorosilicate) | Ca₂Al₃(SiO₄)₃(OH) | 6 - 7 | Orthorhombic | Heat |
| Blue Topaz | Topaz (Fluorosilicate) | Al₂SiO₄(F,OH)₂ | 8 | Orthorhombic | Irradiation, Heat |
Hardness and Durability: The most significant difference among the three lies in their hardness on the Mohs scale. Blue topaz, with a hardness of 8, is the most durable and resistant to scratching, making it an excellent choice for rings and everyday wear. Tanzanite ranks between 6 and 7, placing it in the moderately durable category; it is suitable for most jewelry but can be scratched by harder materials and requires some care. Turquoise, with a hardness of only 5 to 6, is the softest of the group. It is susceptible to scratching and can be damaged by chemicals, perfumes, and even prolonged exposure to sunlight, which can cause its color to fade. To improve its durability for jewelry use, turquoise is often "stabilized" (a process that impregnates the stone with a clear resin) or waxed.
Color and Clarity: Color is the primary driver of value for all three gemstones. For tanzanite, the most prized color is the vivid, saturated violet-blue known as "blue," though many stones exhibit a strong pleochroism, showing different colors (red, purple, blue) when viewed from different angles. It is typically a very clean stone, with high clarity being common. Turquoise's value is determined by its color and matrix. The most desirable color is an even, intense "robin's egg blue," and the presence and pattern of the dark matrix can either detract from its value or, in some cases, create attractive spiderweb patterns that are highly sought after. Blue topaz is valued for its exceptional clarity and brilliance. The most popular shades include the pale "Sky Blue," the medium "Swiss Blue," and the deep, dramatic "London Blue."
Cut and Carat: All three gemstones are cut into a wide variety of shapes and styles to maximize their color and light performance. Tanzanite is often cut in emerald or pear shapes to enhance its depth of color. Topaz, being harder and more brilliant, is often cut into faceted rounds or ovals that showcase its clarity. Turquoise is most commonly seen in cabochon form (a smooth, polished dome) to display its unique color and matrix, though it can also be carved into intricate figures. All three are available in a range of sizes, making them versatile for different types of jewelry, from delicate pendants to bold statement pieces.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, the December birthstones are steeped in symbolism and metaphysical lore that has been passed down through generations.
Turquoise is perhaps the most famous of the three for its protective powers. It has long been regarded as a holy stone, a talisman of good fortune, and a conduit for communication with the spiritual world. Many cultures believed it could warn its wearer of danger by changing color, and it was often used to guard against falls, particularly for horseback riders. It is also associated with healing, wisdom, and tranquility, and is considered a stone of emotional balance.
Tanzanite, as a modern discovery, has more recently been imbued with meaning. It is often associated with transformation, spiritual awakening, and a higher consciousness. Its location near Mount Kilimanjaro, the highest peak in Africa, lends it an air of majestic spirituality. It is said to promote a calm, meditative state and to be particularly effective for those who are developing their intuition or psychic abilities. Its properties of truth and clarity are also frequently cited.
Blue Topaz is associated with calmness, clarity, and communication. It is believed to soothe the mind, relieve stress, and promote honest and clear expression. In the Middle Ages, it was said to dispel enchantment and break curses. Its icy blue color is linked to the throat chakra, making it a popular stone for public speakers, performers, and anyone who wishes to improve their communication skills. It is also thought to attract love and abundance, making it a versatile stone for both personal and professional growth.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone jewelry, and the differences in hardness among the December stones mean they require distinct approaches.
Turquoise: Due to its porosity and softness, turquoise requires the most gentle care. It should be cleaned with a soft, dry cloth. Avoid using any chemicals, including household cleaners, soap, and even some cosmetics, as they can damage the stone's surface and color. Ultrasonic and steam cleaners are strictly forbidden. Store turquoise jewelry separately to prevent it from being scratched by harder stones.
Tanzanite: This gemstone can be cleaned with warm water, a mild soap, and a soft brush. It is important to rinse it thoroughly to remove any soap residue. While it is relatively tough for its hardness, it can be brittle and should be protected from sharp blows and extreme temperature changes. Ultrasonic cleaners should be avoided, and steam cleaning is not recommended.
Blue Topaz: As the most durable of the trio, blue topaz is easier to care for. It can be safely cleaned with warm soapy water and a soft brush. It can also be cleaned in an ultrasonic cleaner, but it is best to avoid sudden temperature changes. Because some topaz can be sensitive to prolonged exposure to strong light, it is advisable to store it in a dark place when not being worn, especially if it has been treated with irradiation (though all commercially available blue topaz is safe and stable).
Conclusion
The December birthstones—tanzanite, turquoise, and blue topaz—offer a remarkable trifecta of color, history, and science. From the ancient, protective charm of turquoise to the singular, modern elegance of tanzanite and the brilliant, accessible clarity of blue topaz, each gem provides a unique expression for those born in the final month of the year. Their diverse origins, from the arid mines of the American Southwest to the singular foothills of Mount Kilimanjaro and global deposits of topaz, underscore the incredible geological forces that create these treasures. Whether chosen for their beauty, their symbolic meaning, or their scientific properties, these three gems continue to captivate and inspire, providing a perfect, multifaceted tribute to the winter month they represent.