For those born in the final month of the year, the gift of birthstone jewelry is not merely a single choice but a vibrant spectrum of blue-hued treasures. December stands uniquely privileged among the months, offering a selection of gemstones that reflect the cool elegance of the winter season. In the United Kingdom, a nation with a deep-seated tradition in gemstone appreciation and jewelry craftsmanship, the December birthstones—Tanzanite, Turquoise, and Blue Topaz—are revered for their rarity, distinct histories, and profound symbolism. While Blue Zircon is also frequently cited as a traditional alternative, the primary focus in the UK market often centers on the former trio.
These gemstones are more than just decorative accents; they are geological marvels, each possessing unique properties that have captivated collectors and jewelers for decades. From the deep, shifting violet-blue of Tanzanite, a stone of immense rarity found in a single location on Earth, to the ancient, opaque charm of Turquoise, used by civilizations for millennia, and the brilliant, sky-clear fire of Blue Topaz, each stone tells a story of formation, culture, and aesthetic appeal. This article delves into the history, geological origins, gemological properties, and cultural significance of these three prominent December birthstones, providing a detailed guide for gemstone enthusiasts, jewelry buyers, and students of gemology within the UK and beyond.
History and Lore: The Journey to a Modern Birthstone
The tradition of assigning specific gemstones to months of the year is an ancient practice, with roots tracing back to civilizations such as the Babylonians and the Hebrews. These early cultures believed that gemstones held protective and symbolic powers, associating each stone with a specific month to bestow its unique benefits upon the wearer. This practice evolved over centuries, influenced by cultural, religious, and eventually commercial factors, culminating in the standardization of the modern birthstone calendar in the 20th century by various jewelers and gemological institutions.
For December, the selection of gemstones reflects the month’s unique position as the year’s finale. The UK’s recognition of December’s birthstones includes Tanzanite, Turquoise, Blue Topaz, and, in some traditions, Blue Zircon. Each of these stones has a distinct journey to its current status.
Tanzanite is the most recent addition to the December birthstone list, making its appearance on the gemological stage in the 1960s. Initially discovered in Tanzania and known as blue zoisite, it was subsequently renamed in honor of its country of origin and its captivating blue color, a marketing effort that rapidly elevated its profile. Its inclusion as a modern birthstone speaks to its rapid rise in popularity and desirability.
Turquoise, in stark contrast, is one of the oldest known gemstones in human history. Its use dates back thousands of years, with ancient civilizations employing it for both adornment and spiritual purposes. The very name "turquoise" is derived from the French phrase pierre turquoise, meaning "Turkish stone," reflecting its historical trade route through Turkey to Europe. Its enduring legacy as a stone of protection and good fortune has made it a timeless choice.
Blue Topaz, while sharing a name with the ancient topaz, has a more modern story regarding its vibrant blue hue. While natural blue topaz exists, the intense, sky-blue varieties popular in contemporary jewelry are often the result of irradiation and heat treatment of colorless topaz. Its affordability and versatility have made it a staple in the UK jewelry market, offering a brilliant, clear blue alternative.
Blue Zircon, the traditional alternative, is one of the oldest birthstones for December, often appearing on lists from the 19th and early 20th centuries. It should not be confused with the cubic zirconia man-made simulant; natural zircon is a distinct natural gemstone with high brilliance and fire.
Geological Formation and Global Sources
Understanding the origin of these gemstones enhances appreciation for their rarity and value. Each stone forms under unique geological conditions and is sourced from specific, often limited, regions of the world.
Tanzanite is arguably the most geographically restricted of all gemstones. It is found in only one small area of the world: the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. This extreme rarity contributes significantly to its value and allure. The gemstone is a variety of the mineral zoisite and owes its signature violet-blue color to trace amounts of vanadium, along with a careful process of heat treatment which is almost always required to bring out the desirable blue hues from its naturally brownish-green state.
Turquoise is an opaque mineral that forms when water containing copper and aluminum seeps through pre-existing rocks, creating hydrated copper aluminum phosphate. Its formation is often associated with arid regions where surface water can percolate down and react with rocks rich in these elements. Major sources for high-quality turquoise include Iran (historically known as Persian turquoise), the United States (particularly Arizona and Nevada), Tibet, and India. The stone’s color and matrix (the host rock remnants) vary significantly depending on its specific mining location.
Blue Topaz is a silicate mineral of aluminum and fluorine that crystallizes in igneous rocks, particularly in pegmatites and high-temperature veins. While topaz is found in various locations globally, the sources for the large, clean crystals used to produce the vibrant blue stones seen in jewelry are primarily Brazil. Other sources include Nigeria, Madagascar, and Pakistan. The transformation from colorless to deep blue is an example of gemstone enhancement, a common and accepted practice in the industry.
Gemological Properties
The physical and optical characteristics of a gemstone determine its durability, appearance, and suitability for jewelry. The following table summarizes key properties for Tanzanite, Turquoise, and Blue Topaz based on standard gemological data.
| Gemstone | Mineral Group | Chemical Formula | Mohs Hardness | Crystal System | Typical Treatments |
|---|---|---|---|---|---|
| Tanzanite | Zoisite | Ca2Al3(SiO4)3(OH) | 6.5 - 7 | Orthorhombic | Heat |
| Turquoise | Phosphate | CuAl6(PO4)4(OH)8·4H2O | 5 - 6 | Triclinic (massive) | Stabilization, Waxing |
| Blue Topaz | Silicate | Al2SiO4(F,OH)2 | 8 | Orthorhombic | Irradiation, Heat |
| Blue Zircon | Zircon | ZrSiO4 | 6.5 - 7.5 | Tetragonal | Heat |
Tanzanite possesses a hardness of 6.5 to 7 on the Mohs scale, making it reasonably durable but susceptible to chipping if struck with force. It exhibits strong pleochroism, appearing blue in one direction and burgundy in another, a property that lapidaries must carefully consider when cutting the stone. Its refractive index is in the range of 1.691 to 1.700.
Turquoise is significantly softer, with a Mohs hardness of 5 to 6. This makes it more susceptible to scratching and damage, requiring careful handling. It lacks the crystal structure of other gems and is typically found as massive, cryptocrystalline aggregates. Its color is derived from copper, while iron can cause greenish tints. Due to its porous nature, turquoise is often treated with wax or oil to seal its surface and enhance its color and luster. Stabilized turquoise, where the stone is impregnated with a clear resin, is also common to improve durability.
Blue Topaz is a much harder gemstone, rating an 8 on the Mohs scale, making it exceptionally durable and ideal for all types of jewelry, including rings and bracelets that are subject to daily wear. Its transparency and high refractive index (1.609-1.627) give it excellent brilliance when cut properly. The most prized shades are the deep "London Blue" and the lighter "Sky Blue."
Blue Zircon is known for its exceptional brilliance and fire, which rivals that of diamond. It has a hardness of 6.5 to 7.5, but like Tanzanite, it can be brittle and prone to chipping due to its tetragonal crystal structure and perfect cleavage in one direction. Most blue zircon on the market has been heat-treated from brownish material to achieve its attractive blue color.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December’s birthstones are deeply imbued with symbolic meaning and metaphysical beliefs, a tradition that continues to resonate with many modern wearers.
Tanzanite is often associated with transformation, new beginnings, and spiritual awakening. Its rapid emergence in the gem world is seen as symbolic of modernity and progress. It is believed to foster compassion, calmness, and a deeper understanding of one's own unique path.
Turquoise is universally recognized as a stone of protection, good fortune, and spiritual grounding. Ancient cultures believed it could ward off evil and protect the wearer from harm. It is also linked to truth, communication, and tranquility, making it a popular amulet for travelers and warriors of old.
Blue Topaz is associated with clarity of thought, calmness, and emotional balance. It is often called the "stone of love and good fortune," believed to attract prosperity and enhance creativity. Its cool blue color is linked to the throat chakra, promoting clear and honest communication.
Blue Zircon is traditionally associated with wisdom, honor, and purity. It was believed to promote a sense of balance and to help the wearer achieve their goals. Its brilliance was thought to light the way in the darkness.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of any gemstone jewelry. The different hardness and structural properties of December’s birthstones necessitate specific care routines.
Tanzanite requires gentle handling. With a hardness of 6.5-7, it is durable enough for most jewelry but should be protected from sharp blows and extreme temperature changes, which can cause fracturing. It is best cleaned with warm water, a mild soap, and a soft brush. Ultrasonic and steam cleaners should be avoided as the vibrations and heat can damage the stone.
Turquoise, being the softest of the group, is highly porous and sensitive to chemicals. It should be protected from cosmetics, perfumes, and lotions, which can discolor it. Cleaning should be done with a soft, dry cloth. Avoid soaking it in water or using any chemical cleaners. Waxed or stabilized turquoise is slightly more resilient but still requires careful treatment.
Blue Topaz is relatively easy to care for due to its high hardness. It can be cleaned with warm soapy water and a soft brush. It is generally safe to use an ultrasonic cleaner, but steam cleaning is not recommended as the heat can potentially cause internal fractures if the stone has been treated or has inclusions.
Blue Zircon is somewhat brittle and should be handled with care to avoid chipping. It is sensitive to heat, so it is advisable to avoid ultrasonic cleaners and high temperatures. Warm soapy water and a soft brush are the safest cleaning methods.
Conclusion
The birthstones of December—Tanzanite, Turquoise, and Blue Topaz—offer a remarkable diversity of color, history, and character. From the single-source rarity of Tanzanite to the ancient legacy of Turquoise and the brilliant durability of Blue Topaz, each gemstone provides a unique and meaningful option for those born in the year's final month. In the UK, these stones are not only celebrated for their aesthetic appeal in jewelry design but are also valued for their rich geological origins and the symbolic meanings they carry. Whether chosen for their protective lore, their vibrant hues, or simply their natural beauty, these blue treasures continue to be cherished as timeless additions to any jewelry collection.