In the realm of gemstones, December is uniquely represented by not one, but three distinct birthstones: tanzanite, turquoise, and blue topaz. Each stone offers a captivating palette of blues and violets, perfectly mirroring the crisp air and serene beauty of the winter month. While they differ vastly in their geological origins and physical properties, all three share a common association with tranquility, wisdom, and protection, making them cherished choices for jewelry that is both personal and meaningful. This article delves into the distinct characteristics of each December birthstone, exploring their gemological properties, symbolic significance, and the practical considerations for their care and selection.
The Three Gems of December: An Overview
The modern birthstone list, standardized by the American Gem Society, recognizes tanzanite, turquoise, and blue topaz as the official gems for December. This trio provides a remarkable range of color and style. Tanzanite is celebrated for its mesmerizing pleochroism, displaying shades of blue, violet, and burgundy depending on the viewing angle. Turquoise, an ancient and opaque stone, is prized for its vibrant blue-green hue and distinctive matrix patterns. Blue topaz, particularly in its intense "London Blue" variety, offers a deep, saturated blue that rivals the finest sapphires. Together, they offer a versatile spectrum for December-born individuals and jewelry enthusiasts.
Tanzanite: The Violet-Blue Wonder
Geological Formation and Sources
Tanzanite is a relative newcomer to the gem world, with its discovery traced to the 20th century. It is a variety of the mineral zoisite and is found in only one location on Earth: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This incredibly limited geographic source makes tanzanite a truly rare gemstone. The formation of tanzanite is linked to a unique geological event where intense heat and pressure transformed the parent rock, a process that occurred approximately 585 million years ago during the Neoproterozoic Era. The mining of tanzanite is a significant industry in the region, though the deposits are finite, contributing to its value and allure.
Gemological Properties
Tanzanite is a member of the zoisite group, with a chemical composition of Ca₂Al₃(SiO₄)₃(OH). It has a hardness of 6.5 to 7 on the Mohs scale, making it suitable for jewelry but requiring some care to avoid scratches from harder materials. Its most defining characteristic is its strong trichroism (a form of pleochroism), where the stone can appear blue, violet, and a reddish-brown from different crystal directions. Most tanzanite available on the market has been heat-treated to enhance its blue and violet colors, a standard and permanent practice accepted by the gemological community. The refractive index of tanzanite typically ranges from 1.691 to 1.700.
Symbolism and Lore
Tanzanite is often associated with modern spiritual beliefs, with some sources claiming it promotes spiritual awakening, compassion, and a higher consciousness. It is frequently linked to the throat and third eye chakras in crystal healing practices, believed to facilitate clear communication and intuition. While its lore is not as ancient as other gems, its rapid rise in popularity has imbued it with contemporary significance as a stone of transformation and new beginnings.
Turquoise: The Ancient Stone of Protection
Historical Significance and Lore
Turquoise is one of the oldest gemstones known to humanity, with a history spanning thousands of years across numerous cultures. It has been treasured for centuries by ancient civilizations, including the Egyptians, Persians, and Native American tribes of the Southwestern United States. Its name derives from the French "pierre turquoise," meaning "Turkish stone," as it was brought to Europe from Persia via Turkey. Historically, turquoise has been a powerful talisman. It was believed to offer protection, luck, and healing. For instance, ancient warriors and aviators often wore turquoise for safeguarding. It is also strongly associated with wisdom, tranquility, and good fortune. In many cultures, it is considered a sacred stone that connects the wearer to the natural world and the spiritual realm.
Geological Formation and Sources
Turquoise is an opaque, mineral that forms in arid regions where acidic, copper-rich water seeps through pre-existing rock. The water reacts with minerals containing aluminum and phosphorus, slowly depositing turquoise in veins and nodules. The distinctive blue-green color comes from copper, while iron can create a greenish hue, and the matrix (the host rock) patterns are unique to each deposit. Major sources of turquoise include the United States (notably Arizona, Nevada, and New Mexico), Iran (Persian turquoise), and China. The stone's quality is often judged by its color, matrix, and hardness.
Gemological Properties
Turquoise is a phosphate mineral with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It has a hardness of 5 to 6 on the Mohs scale, making it relatively soft and prone to scratching and chemical damage. It is not transparent and has a waxy to vitreous luster. Turquoise is often treated to enhance its color and durability, with common methods including waxing, oiling, and stabilization (impregnating the stone with a clear resin). These treatments are widely accepted in the trade, provided they are disclosed.
Blue Topaz: The Icy Blue Beauty
Geological Formation and Sources
Blue topaz is a variety of the topaz mineral, which is a silicate containing fluorine and aluminum. While topaz can be found in many locations worldwide, the deep blue varieties used in jewelry are almost always created through the irradiation and heat treatment of colorless or pale topaz. The natural colorless topaz is typically sourced from Brazil, Nigeria, Sri Lanka, and the United States (specifically Utah and Texas). The treatment process, which is permanent and stable, is what produces the coveted "Swiss Blue," "London Blue," and "Sky Blue" shades. The origin of the raw topaz is therefore distinct from the final blue color, which is an industry-standard enhancement.
Gemological Properties
Topaz has a chemical composition of Al₂SiO₄(F,OH)₂ and a hardness of 8 on the Mohs scale, making it an exceptionally durable gemstone ideal for rings and daily-wear jewelry. It has perfect basal cleavage, meaning it can be split along certain planes, so it requires careful cutting and setting. Blue topaz has a refractive index of approximately 1.619 to 1.627. Its color ranges from a very light, pale blue (Sky Blue) to a deep, saturated blue (London Blue). The most intense blues are the result of the treatment process, and they are highly valued for their vivid, ink-like appearance.
Symbolism and Lore
Blue topaz is traditionally associated with communication, clarity, and emotional balance. It is often called the "stone of truth" and is believed to aid in honest self-expression and calm decision-making. Some historical beliefs attributed healing properties to topaz, including the ability to alleviate insomnia and asthma. In modern metaphysical practices, blue topaz is linked to the throat chakra, similar to tanzanite, and is thought to promote peaceful communication and soothe the spirit.
Care and Cleaning for December Birthstones
Proper care is essential to maintain the beauty and longevity of these gemstones, given their differing physical properties. The following table summarizes key care instructions based on their Mohs hardness and chemical sensitivities.
| Gemstone | Mohs Hardness | Key Vulnerabilities | Recommended Care |
|---|---|---|---|
| Tanzanite | 6.5 - 7 | Susceptible to scratching; can be brittle. | Clean with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes. Store separately from harder gems. |
| Turquoise | 5 - 6 | Soft, porous, and sensitive to chemicals, lotions, and acids. | Wipe clean with a soft, dry cloth. Avoid water, detergents, and cosmetics. Never use an ultrasonic or steam cleaner. |
| Blue Topaz | 8 | Perfect cleavage; can be chipped if struck. | Clean with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but avoid steam. Be cautious of physical impacts. |
For all three stones, it is advisable to remove jewelry before engaging in activities that could cause impact or exposure to harsh chemicals, such as cleaning, gardening, or swimming.
Selecting December Birthstone Jewelry
When choosing jewelry featuring these December birthstones, several factors come into play. For tanzanite, look for stones with a vibrant, evenly distributed blue-violet color and good clarity. As a relatively soft stone, it is often set in protective settings like bezels for rings. Turquoise selection is highly personal, with preferences for specific colors (from sky blue to greenish teal) and matrix patterns. High-quality turquoise is typically hard and not easily scratched. For blue topaz, the intensity and evenness of the blue color are paramount. London Blue topaz, with its deep, rich hue, is particularly popular for statement pieces. The durability of topaz makes it an excellent choice for engagement rings and other frequently worn jewelry.
The variety within the December birthstone trio ensures there is a perfect match for every style and preference, from the ancient, earthy charm of turquoise to the modern, ethereal glow of tanzanite and the classic, icy brilliance of blue topaz.
Conclusion
The December birthstones—tanzanite, turquoise, and blue topaz—form a compelling triad that captures the essence of winter with their serene blue and violet hues. Each gemstone possesses a unique narrative: tanzanite, the rare and recent discovery from Tanzania, enchants with its dramatic color play; turquoise, the ancient protector, carries millennia of cultural significance and symbolic power; and blue topaz, the durable and vividly colored gem, offers brilliant clarity and depth. Together, they provide a rich palette for personal expression, whether chosen for their beauty, their symbolic meanings, or their connection to the month of December. Understanding their distinct origins, properties, and care requirements allows enthusiasts to appreciate these gems not just as decorative items, but as remarkable products of Earth's geological artistry.