The month of December is unique in the gemological calendar, holding the distinction of having the highest number of official birthstones. While most months are assigned a single gem, or perhaps two, December boasts a quartet of radiant options: Blue Topaz, Blue Zircon, Tanzanite, and Turquoise. This abundance offers a remarkable variety for those born in the final month of the year, each stone reflecting the cool, wintry palette of the season with its icy blues and deep twilight hues.
The existence of four birthstones for one month is not an ancient tradition but a relatively modern development, driven by the expansion of gemstone markets and consumer demand. The official list has evolved over time, with stones being added to offer greater choice in terms of color, availability, and cost. These four gems, while all sharing a dominant blue coloration, possess vastly different histories, geological origins, and physical properties. From the ancient protective amulet of Turquoise to the modern marvel of Tanzanite, each gem tells a unique story. This article will explore the history, geology, gemological characteristics, and cultural significance of each of December's four birthstones, providing a comprehensive guide for gemstone enthusiasts, collectors, and anyone captivated by their beauty.
History and Lore: The Evolution of December's Gems
The story of December's birthstones is a tale of both ancient tradition and modern commerce. The standardization of birthstones began in 1912 when the National Association of Jewelers sought to create an official list, blending historical customs with gemstones that were practical for the jewelry industry. This list has been updated several times since, reflecting new discoveries and changing tastes.
Turquoise is the most ancient of the four, recognized as one of the oldest known birthstones. Its history spans millennia and continents, deeply embedded in cultures from ancient Egypt to the indigenous peoples of the American Southwest. For these cultures, Turquoise was not merely an ornament but a powerful talisman, believed to offer protection and good fortune.
Zircon was officially added to December's list in 1952 by the Jewelry Industry Council of America. A gem with a long history of its own, Zircon has been prized for centuries for its exceptional brilliance, which is so intense it is often mistaken for diamond. Its addition to the birthstone list provided a sparkling, durable option for December-born individuals.
Tanzanite is the newest addition, having been included in the list in 2002. Its discovery in the mid-20th century was a major event in the gem world. As a relative newcomer, it represents transformation and new beginnings, a fitting symbolism for a gem that has so rapidly ascended to prominence.
Blue Topaz, while a popular modern choice, has a more ambiguous historical origin. It has been found throughout history, but its exact provenance is unknown. It became a prominent December option due to its stunning blue color and increased availability in the market. Its addition reflects the trend of offering a variety of colors and styles to suit personal preferences.
The question of why December has four birthstones while other months have one or two is often answered by commercial practicality. The multiple options provide variety in color, durability, and price, making the stones accessible to a broader range of consumers.
Geological Formation and Mining Locations
Each of the four December birthstones has a distinct geological story and is sourced from specific regions of the world, contributing to its rarity and value.
Turquoise is a secondary mineral that forms when water containing copper and aluminum seeps through rocks. This process creates nodules and veins in arid regions. While Turquoise is found in many parts of the world, including Iran, Egypt, and China, a significant portion of the material used in jewelry comes from the Southwestern United States, particularly states like Arizona and New Mexico.
Zircon is a mineral belonging to the nesosilicate group. It is one of the oldest minerals on Earth, found in the crust of the planet. It is mined from alluvial deposits, where water has eroded the host rock and concentrated the durable Zircon crystals. Major sources for gem-quality Zircon include Australia, Cambodia, Sri Lanka, and Thailand.
Tanzanite is the rarest of the four December birthstones, a fact that contributes significantly to its high value. It is a variety of the mineral zoisite and is found in only one location on the entire planet: the Merelani Hills of northern Tanzania. Its discovery in 1967 and subsequent limited supply make it an exceptionally rare gemstone.
Blue Topaz is a silicate mineral composed of aluminum and fluorine. While natural blue topaz exists, it is typically very light in color. Most of the vivid blue topaz seen in the market today is the result of treating colorless or pale topaz with irradiation and heat. Topaz is mined in various locations globally, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States. It is notable that Blue Topaz is the official state gem of Texas.
Gemological Properties: A Scientific Comparison
Understanding the physical and chemical properties of these gems is crucial for appreciating their unique characteristics and for making informed decisions about their use in jewelry and care.
| Gemstone | Chemical Composition | Hardness (Mohs Scale) | Luster | Key Characteristics |
|---|---|---|---|---|
| Blue Topaz | Aluminum Silicate, Fluorine | 8 | Glass-like | Prone to deep cleavage, making it delicate despite its hardness. Most commercial color is from treatment. |
| Zircon | Zirconium Silicate | 6.5 - 7.5 | Adamantine | High refractive index gives it exceptional brilliance, rivaling diamond. |
| Tanzanite | Calcium Aluminum Silicate | 6 - 6.5 | Vitreous | Trichroic, showing blue, violet, and reddish hues depending on crystal orientation. |
| Turquoise | Hydrated Copper Aluminum Phosphate | 5 - 6 | Waxy to subvitreous | Often contains matrix (host rock) and is prized for its unique, opaque blue-green color. |
Blue Topaz: The Durable Modern Choice
Blue Topaz is the hardest of the December birthstones, ranking an 8 on the Mohs hardness scale. This makes it a durable choice for everyday jewelry. However, despite its hardness, it possesses deep cleavage, meaning it can be chipped or broken if struck with sufficient force against a cleavage plane. Its chemical makeup is that of a silicate mineral composed of aluminum and fluorine. The gem exhibits a glass-like luster. As mentioned, the vibrant blues of varieties like London Blue (deep, inky blue), Swiss Blue (vibrant, medium light blue), and Sky Blue (light aqua) are typically achieved through the irradiation of naturally colorless topaz.
Zircon: The Diamond Imitator
Zircon is a zirconium silicate mineral that ranks between 6.5 and 7.5 on the Mohs scale, making it reasonably durable for jewelry. Its most defining feature is its adamantine luster and high refractive index, which gives it a brilliance and "fire" that is second only to diamond. This exceptional sparkle is why Zircon has historically been used as a diamond simulant. It is important to distinguish Zircon from synthetic cubic zirconia, a completely different material.
Tanzanite: The Rare Trichroic Gem
Tanzanite is a variety of the mineral zoisite and has a chemical composition of calcium aluminum silicate. With a Mohs hardness of 6 to 6.5, it is more delicate than Topaz or Zircon and requires careful handling to avoid scratches and damage. Its most remarkable property is its trichroism—the ability to display three different colors when viewed from different crystal directions. A single Tanzanite crystal can appear blue, violet, and a reddish-brown simultaneously. This dynamic color play, combined with its extreme rarity, makes it the most valuable of the December birthstones.
Turquoise: The Ancient Opaque Mineral
Turquoise is an opaque, hydrated copper aluminum phosphate mineral. Its hardness is relatively low, ranging from 5 to 6 on the Mohs scale, making it the softest and most delicate of the four December gems. It is often found with a matrix, which is the remnants of the host rock in which it formed, creating unique, web-like patterns that are highly valued by connoisseurs. Its luster is typically waxy to subvitreous. Due to its porosity and softness, it is often stabilized or treated to enhance its durability and color.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, gemstones have been imbued with meaning and power. Each of December's birthstones carries a rich tapestry of symbolism.
- Turquoise is widely regarded as a stone of protection, grounding, and good fortune. For centuries, it has been used as a talisman to ward off negative energy and bring peace to the wearer. Many turn to it for a sense of calm and stability when life feels chaotic.
- Tanzanite is a modern symbol of transformation, new beginnings, and clarity. Its unique blue-violet hue is said to reflect the feeling of stepping into a new chapter of life with curiosity and a clear vision. It is associated with spiritual awakening and higher consciousness.
- Zircon is associated with mental clarity, wisdom, and a sense of balance. It is believed to sharpen focus and help the wearer see things with greater perspective and insight.
- Blue Topaz is linked to calm, communication, and serenity. Its cool blue color is reminiscent of the sky and sea, evoking feelings of peace and tranquility. It is often associated with clear and honest expression.
Care and Cleaning: Preserving Your Gemstone
Proper care is essential to maintain the beauty and integrity of any gemstone. The varying hardness and durability of December's gems necessitate different care routines.
Blue Topaz (Hardness 8, Deep Cleavage): Despite its high hardness, Topaz is susceptible to chipping due to its cleavage. Avoid wearing it during activities that could cause impact. To clean, use warm water, a mild soap, and a soft brush. Avoid ultrasonic and steam cleaners, as the vibrations or heat could potentially cause damage along cleavage planes.
Zircon (Hardness 6.5-7.5): Zircon is relatively durable but can be brittle. It is best suited for pendants or earrings rather than rings that receive daily wear. Clean it with warm soapy water and a soft brush. It is generally safe in ultrasonic cleaners, but caution is advised due to its potential for brittleness.
Tanzanite (Hardness 6-6.5): As the softest and most fragile of the non-Turquoise options, Tanzanite requires gentle handling. It is prone to scratching and abrasion. It is highly recommended for occasional wear jewelry like pendants and earrings. Clean with warm soapy water and a soft brush. Keep it away from harsh chemicals and avoid ultrasonic and steam cleaners.
Turquoise (Hardness 5-6, Porous): Turquoise is the most delicate of the four. It is soft, porous, and can be damaged by chemicals, cosmetics, and even the oils from the skin. It should be the last thing you put on and the first thing you take off. Clean it simply with a soft, dry cloth. Avoid water, soap, and all ultrasonic and steam cleaners, as these can damage the stone's color and stability.
Conclusion
The birthstones of December—Blue Topaz, Zircon, Tanzanite, and Turquoise—offer a diverse and fascinating collection for those born in the month. This unique quartet ranges from the ancient, protective talisman of Turquoise to the brilliant, diamond-like sparkle of Zircon; from the rare, transformative beauty of Tanzanite to the modern, durable elegance of Blue Topaz. Each stone possesses a distinct set of gemological properties, a unique geological origin, and a rich history of symbolism. Together, they capture the essence of winter with their cool blue tones, providing a wide array of choices for personal adornment, meaningful gifts, and a deeper connection to the natural world's artistry.