December is a month of profound contrast—crisp, icy skies and deep twilight blues, a time of reflection and celebration. For those born in this winter month, the birthstones are a reflection of this unique season: a trio of cool-toned gems that range from the earthy, ancient turquoise to the vibrant, modern tanzanite and the brilliant zircon. Unlike most months, which are assigned a single gemstone, December is uniquely associated with multiple stones, offering a palette of choices that have evolved over time. This abundance is rooted in history, commerce, and the desire to provide variety in color, durability, and price. The primary December birthstones recognized today are turquoise, zircon, and tanzanite, with blue topaz often included as a popular modern alternative. Each stone carries its own distinct history, geological origin, gemological properties, and cultural symbolism, making the choice of a December birthstone a deeply personal journey.
This article will explore the rich tapestry of December's birthstones in detail. We will delve into the historical journey of each gem, from ancient amulets to modern jewelry showcases. We will examine their geological formation and the specific mining locations that make them unique. The scientific properties that define their appearance and durability will be laid out, providing a clear guide for collectors and jewelry buyers. Furthermore, we will unpack the layers of symbolism and metaphysical beliefs that have been attached to these stones across different cultures and eras. Finally, practical advice on care and cleaning will be provided to ensure these beautiful gems can be cherished for generations. By understanding the origins and characteristics of turquoise, zircon, tanzanite, and blue topaz, one can fully appreciate why December is often described as a month of gemstone treasure.
History and Lore: A Journey Through Time
The history of December's birthstones is as multifaceted as the stones themselves, with each gem carrying a legacy that spans continents and millennia. The tradition of associating specific gems with months is believed to have roots in the biblical description of the High Priest's breastplate, which featured twelve stones representing the tribes of Israel. Over centuries, this concept evolved, with the modern birthstone list being standardized in 1912 by the National Association of Jewelers in the United States, later updated by the Jewelry Industry Council of America in 1952 and 2002.
Turquoise is arguably the most ancient of December's gems. Its name derives from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe from the mines of Persia (modern-day Iran) via the gem markets of Constantinople, Turkey. Historical records indicate it was a favored gem for amulets from the earliest times, prized for its relative ease of cutting and ability to hold inscriptions. In ancient cultures, it was believed to possess protective powers against danger and was expected to bring good fortune. It was particularly meaningful to lovers and married couples, thought to safeguard relationships and preserve friendship when given as a gift. A unique belief held that the stone would warn its wearer of impending illness or danger by becoming pale. In Tibet, turquoise was considered a birthstone of fortune, health, and success, and was so valued it was used as currency. The ancient Incas and Mayas offered turquoise as gifts to their gods, while Native American tribes of the Southwest associated it with youth and strength.
Zircon is one of the oldest minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. However, its association with December is more modern. While it has been used in jewelry for centuries, it was formally added to the December birthstone list in 1952. Historically, it was sometimes confused with other blue gemstones like sapphire or diamond due to its high brilliance. For centuries, it was believed to promote honor, wisdom, and prosperity in its wearer.
Tanzanite is the newest of the December birthstones, with a history that is remarkably brief. It was not recognized as a distinct gemstone until 1967 and was added to the official birthstone list in 2002. Its discovery is attributed to a single source in Tanzania, making it a geological marvel of the modern era. Its rapid ascent to birthstone status highlights how the list can evolve with new discoveries and commercial appeal.
Blue Topaz, while not always listed as a primary birthstone in all historical lists, has gained significant popularity in modern times. Its exact historical origins are less clear, but it has been found in various archaeological contexts. It was added to the December list by the Jewelry Industry Council of America in 1952, alongside zircon. The expansion of the December list to include multiple stones, including blue topaz, is often attributed to the desire to offer consumers more affordable and durable options for jewelry.
Geological Formation and Sources
The genesis and mining locations of these gems are as diverse as their histories, ranging from ancient, scattered deposits to a single, unique source.
Turquoise is a secondary mineral formed by the interaction of water with pre-existing aluminum-rich rocks, typically in arid regions. It is found in veins and nodules within host rock. Major sources are geographically distinct. Historically, the finest quality turquoise came from Persia (modern-day Iran), known for its intense sky-blue color with minimal matrix. In the United States, significant deposits are found in the Southwest, particularly in Arizona and New Mexico, where turquoise often contains a distinctive brown or black matrix. Other notable sources include Tibet, China, and parts of Africa. The stone's color and matrix pattern are directly influenced by the specific mineral composition of the local host rock and water.
Zircon is a zirconium silicate mineral that forms in the cooling of magma. It is found in igneous and metamorphic rocks worldwide. The primary sources for gem-quality zircon are found in Australia (particularly the state of New South Wales), Sri Lanka, Thailand, Cambodia, and Vietnam. Australian zircon is often associated with a range of colors, while Sri Lankan deposits are famous for producing high-quality blue zircon, which is often heat-treated to achieve its vibrant blue hue.
Tanzanite is uniquely sourced. It is found in only one location on Earth: a small mining area in the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. This extreme rarity is a key factor in its value and mystique. The gem forms under specific geological conditions involving the metamorphism of calcium-rich rocks, and its discovery is a relatively recent event in gemological history.
Blue Topaz is a silicate mineral of aluminum and fluorine. Natural blue topaz is rare, and most commercial blue topaz is produced by irradiating and heat-treating colorless topaz, which is more commonly available. Major sources for topaz include Sri Lanka, Brazil, Mexico, Nigeria, and the United States (with Texas claiming it as its state gem). The treatment process to achieve the blue color is a standard industry practice.
Gemological Properties
Understanding the physical and chemical properties of these stones is crucial for appreciating their beauty and determining their care.
| Gemstone | Chemical Composition | Mohs Hardness | Crystal System | Typical Colors | Special Properties |
|---|---|---|---|---|---|
| Turquoise | Hydrated copper aluminum phosphate | 5 – 6 | Triclinic | Sky blue to greenish-blue | Often contains a matrix (host rock); porous. |
| Zircon | Zirconium silicate | 6.5 – 7.5 | Tetragonal | Colorless, blue, yellow, brown, red | High refractive index; can be radioactive (some brown zircons). |
| Tanzanite | Calcium aluminum hydroxyl silicate | 6 – 6.5 | Orthorhombic | Blue-violet, pleochroic (shows different colors from different angles) | Strong pleochroism; heat-sensitive. |
| Blue Topaz | Aluminum silicate with fluorine and hydroxyl | 8 | Orthorhombic | Light to deep blue (usually treated) | Very durable; often irradiated to achieve color. |
Turquoise has a Mohs hardness of 5 to 6, making it relatively soft and prone to scratching. It is porous, which allows it to absorb oils and chemicals, potentially altering its color over time. Its characteristic blue color comes from copper, while iron can create greenish hues. The presence of the host rock matrix is a common feature, especially in American turquoise.
Zircon is significantly harder, with a Mohs hardness of 6.5 to 7.5, making it suitable for everyday jewelry, though it can be brittle. It has a very high refractive index, giving it a brilliant, diamond-like sparkle. Blue zircon is typically achieved by heat-treating brown zircon, a process that is stable. It is important to note that some brown zircons are radioactive, but gem-quality blue zircon is safe for jewelry.
Tanzanite has a Mohs hardness of 6 to 6.5, making it more delicate than many other gemstones. Its most defining characteristic is its strong pleochroism—it exhibits different colors when viewed from different crystal directions. A single tanzanite crystal can show violet-blue, blue, and burgundy-red depending on the orientation. This property requires careful cutting to display the desired blue-violet hue. It is also heat-sensitive and should not be exposed to high temperatures or sudden temperature changes.
Blue Topaz is the most durable of the December birthstones, with a Mohs hardness of 8. This makes it excellent for daily wear in rings and bracelets. As noted, the deep blue colors of most commercial blue topaz are the result of irradiation followed by heat treatment to stabilize the color. This process is permanent and does not affect the stone's durability.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, these stones are deeply imbued with symbolic meaning and metaphysical beliefs, often passed down through generations.
Turquoise is universally recognized as a stone of protection. It is believed to ward off negative energy, bring good fortune, and promote calm and balance. Many cultures, from Native Americans to Tibetans, have viewed it as a sacred stone. It is also associated with friendship and loyalty, making it a popular gift. The belief that it changes color to warn of danger or illness is a testament to its perceived connection to the wearer's well-being.
Zircon is associated with clarity, wisdom, and balance. It is thought to sharpen focus, aid in decision-making, and promote spiritual growth. Historically, it was believed to bring honor and prosperity to its wearer. Its brilliant sparkle is often linked to mental clarity and enlightenment.
Tanzanite, as a modern discovery, has quickly developed its own symbolism centered on transformation and new beginnings. Its unique color shift is seen as a reflection of change and growth. It is often associated with spiritual awakening and the ability to see the world from new perspectives. It represents stepping into a new chapter with clarity and curiosity.
Blue Topaz is linked to calm, communication, and truth. Its serene blue color is believed to soothe emotions and reduce stress. It is also associated with clarity of thought and honest communication, making it a stone for those who need to express themselves clearly.
Care and Cleaning
Proper care is essential to maintain the beauty and integrity of these gemstones, given their varying physical properties.
Turquoise requires the most careful handling. Due to its porosity and relatively low hardness, it should be protected from chemicals, perfumes, lotions, and even excessive perspiration. Clean it with a soft, dry cloth. Avoid ultrasonic and steam cleaners. Store it separately to prevent scratches.
Zircon is relatively hard but can be brittle. It is best cleaned with warm, soapy water and a soft brush. Avoid sudden temperature changes and harsh chemicals. While durable, it is not as tough as sapphire or ruby, so it should be protected from hard knocks.
Tanzanite is delicate and should be handled with care. It is best cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners, steam cleaners, and any harsh chemicals. Due to its cleavage (a tendency to split along flat planes), it is vulnerable to impact and should be stored in a soft cloth away from other jewelry.
Blue Topaz is the easiest to care for, thanks to its high hardness. It can be cleaned safely with warm, soapy water, an ultrasonic cleaner (if the jewelry setting allows), and even a steam cleaner. It is durable enough for everyday wear, though it is still wise to protect it from hard blows.
Conclusion
December's birthstones offer a remarkable diversity of choice, color, and history. From the ancient, protective turquoise to the brilliant, wise zircon, the transformative tanzanite, and the durable, serene blue topaz, each gem provides a unique connection to the winter month. Their stories are woven from geology, history, and human belief, reflecting both the earth's processes and our own desires for meaning and beauty. Whether chosen for its historical significance, metaphysical properties, or simply its captivating hue, a December birthstone is more than a piece of jewelry; it is a personal emblem of identity, a link to ancient traditions, and a celebration of the cool, deep blues that define the end of the year.