For individuals born in the final month of the year, the birthstone selection is uniquely abundant. Unlike months assigned a single gem, December is represented by a triumvirate of distinct blue stones: Turquoise, Tanzanite, and Zircon. These three gemstones, ranging from ancient talismans to modern discoveries, share a cool color palette that evokes the winter month they symbolize. While Turquoise holds the title of the traditional birthstone, Tanzanite and Zircon have been officially recognized as modern alternatives, offering December-born individuals a spectrum of choice in color, durability, and meaning. This article explores the geological origins, gemological properties, historical lore, and cultural significance of these three remarkable gemstones.
History and Lore: From Ancient Talismans to Modern Discoveries
The history of December's birthstones spans millennia, bridging the ancient world with contemporary gemology. Turquoise stands as the oldest of the trio, a gemstone revered by civilizations across the globe for thousands of years. Its name offers a clue to its journey into Western culture; the word "Turquoise" is derived from the French pierre turquoise, meaning "stone of Turkey." This nomenclature arose because the stone was brought to Europe from Turkish bazaars. Its use, however, predates this trade route by centuries. Historical accounts note that Turquoise has adorned everything from ancient Egyptian pharaohs' burial masks to the jewelry of Native American tribes, establishing its legacy as a stone of protection and status.
In stark contrast to Turquoise’s ancient lineage, Tanzanite is a distinctly modern discovery. This violet-blue gem was unearthed in 1967 in Tanzania, a discovery so significant that the stone was named for its country of origin. Found only in a small, specific area near Mount Kilimanjaro, Tanzanite is considered one of the rarest gemstones in the world. Its introduction to the gem market was rapid; its unique color and rarity led to its quick recognition and subsequent inclusion as a birthstone for December, representing a modern addition to the traditional list.
Zircon, while not as historically ubiquitous as Turquoise, is one of the oldest minerals on Earth, with some specimens dating back billions of years. While Zircon occurs in a variety of colors, it is the blue variety that is specifically associated with December. This sparkling stone is valued for its exceptional brilliance, which rivals that of diamonds. The association of these three stones—Turquoise, Tanzanite, and Zircon—creates a historical narrative that moves from the ancient and enduring (Turquoise) to the exclusive and contemporary (Tanzanite), with Zircon bridging the gap through its ancient mineralogical roots and dazzling physical properties.
Geological Formation and Sources
Understanding the origins of these gemstones reveals why they differ so greatly in appearance, durability, and availability.
Turquoise is a secondary mineral formed by the percolation of groundwater through bedrock. This process involves water rich in copper seeping into the rock, where it reacts with minerals containing aluminum and phosphorus over long periods. These reactions result in the formation of an opaque stone in stunning shades of blue and green. The distinctive dark lines and shapes often seen within Turquoise are actually remnants of the surrounding bedrock, known as "matrix." Major sources for Turquoise include the United States (particularly the Southwest), Iran, Tibet, and India.
Tanzanite owes its existence to a unique geological event. It is a variety of the mineral zoisite and was formed by a massive tectonic shift and intense heat and pressure that altered the chemistry of the host rock. This specific set of conditions occurred in only one location on the planet: a small mining area near Mount Kilimanjaro in Tanzania. This extreme geographic limitation is the primary reason for the stone's rarity.
Zircon is a mineral belonging to the nesosilicates group. It forms in igneous and metamorphic rocks and is found in many parts of the world, including Australia, Cambodia, and Sri Lanka. While it occurs in many colors, the blue variety commonly used for December birthstones is often produced through heat treatment of brown zircon crystals. This process creates the clear, bright blue hue that is most sought after for jewelry.
Gemological Properties: A Scientific Comparison
The three December birthstones differ significantly in their physical and chemical properties, which dictates their durability, care requirements, and value. The following table summarizes the key gemological data available for Turquoise, Tanzanite, and Zircon based on the provided sources.
| Gemstone | Mineral Group | Chemical Composition | Hardness (Mohs Scale) | Color Varieties |
|---|---|---|---|---|
| Turquoise | Phosphate | Hydrated copper/aluminum phosphate | 5 – 6 | Sky blue, greenish-blue |
| Tanzanite | Zoisite (Sorosilicate) | Calcium aluminum hydroxyl sorosilicate | Not specified in sources | Violet-blue (trichroic) |
| Zircon | Nesosilicate | Zirconium silicate | Not specified in sources | Blue (most popular), also gold, red, brown, colorless |
Turquoise is an opaque phosphate mineral containing copper and aluminum. Its hardness on the Mohs scale ranges from 5 to 6, making it relatively soft compared to many other gemstones used in jewelry. This lower hardness level means it is susceptible to scratching and breaking, requiring careful handling. The color of Turquoise is directly linked to its copper content; higher copper levels yield a purer blue, while the presence of iron or zinc can shift the hue toward green.
Tanzanite is a variety of zoisite. A defining gemological feature of Tanzanite is its remarkable trichroism. This property means that the stone displays three different colors depending on the viewing angle: typically blue, purple, and burgundy. This dynamic color play is a result of its crystal structure and the way it absorbs light. While the sources do not specify its hardness, its association with fragility in care instructions suggests it is not as durable as harder gems.
Zircon is a heavy silicate mineral. While the sources do not provide its hardness or chemical formula, they emphasize its high refractive index, which gives it a brilliance and sparkle that can rival diamonds. The blue zircon associated with December is often the result of heat treatment, which transforms naturally brown zircon into a stable, vibrant blue.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these three stones have accumulated a wealth of symbolic meanings and metaphysical beliefs, many of which persist today.
Turquoise is widely regarded as a stone of protection, healing, and good fortune. Its lore is rich with claims of its ability to safeguard the wearer from harm. It has been used as a talisman for thousands of years, believed to offer protection in battle and during travel. Beyond physical protection, Turquoise is also associated with friendship, love, and loyalty, often exchanged as a token of honest affection. It is said to promote wisdom, truth, and clear communication, encouraging the wearer to speak with integrity.
Tanzanite, as a newer gem, has developed a modern mythology centered on transformation and spiritual awakening. Its striking violet-blue color is linked to higher consciousness and intuition. It is often associated with new beginnings and is believed to help its wearer navigate change with clarity and purpose. Some sources attribute to it the power to unite the mind and heart, fostering a sense of calm and deep understanding.
Zircon is linked to wisdom, balance, and clarity. As one of the oldest minerals, it is thought to possess grounding energy that connects the wearer to the earth. It is believed to help clear mental blocks, promote self-confidence, and aid in achieving a state of spiritual equilibrium. The brilliance of Zircon is often seen as a reflection of inner light and clarity of thought.
Care and Cleaning: Preserving the Gems
Given their distinct gemological properties, the care required for each of the December birthstones varies significantly. Proper maintenance is essential to ensure their longevity and beauty.
Turquoise, with its hardness of only 5 to 6 and its porous nature, is the most delicate of the three. It is susceptible to damage from chemicals, heat, and even prolonged exposure to skin oils and lotions, which can cause discoloration. Cleaning Turquoise should be done gently using warm water, a mild soap, and a soft cloth. It should never be cleaned with ultrasonic cleaners or steam. To protect it from scratches, it should be stored separately from harder gemstones.
Tanzanite is considered fragile. While specific hardness data is not provided, sources describe it as delicate. It is prone to scratching and breaking if knocked against hard surfaces. To clean Tanzanite, use warm water, a mild detergent, and a soft brush. As with Turquoise, ultrasonic cleaners and steam cleaning are not recommended as they can damage the stone.
Zircon is generally more durable than Turquoise and Tanzanite, though it can be brittle due to its high refractive index and crystal structure. It is important to protect Zircon from hard blows that could fracture it. Cleaning can be done with warm soapy water and a soft brush. It is generally safe for use in an ultrasonic cleaner, but it is always best to exercise caution. Because some Zircon may be treated with heat to achieve its blue color, extreme temperature changes should be avoided.
Conclusion
The birthstones of December—Turquoise, Tanzanite, and Zircon—offer a compelling study in contrast and harmony. They represent a spectrum of geological time, from the ancient formation of Zircon and the millennia-old history of Turquoise to the recent discovery of Tanzanite. Their colors, ranging from the soft, opaque sky blue of Turquoise to the shifting violet-blue of Tanzanite and the brilliant, clear blue of Zircon, provide a diverse palette for jewelry and personal expression. More than just beautiful gems, they are carriers of deep symbolic meaning, associated with protection, wisdom, transformation, and good fortune. For those born in December, this trio of blue stones provides not just a single choice, but a rich legacy of science, history, and lore to choose from.