December is uniquely represented by a trio of gemstones, each celebrated for its distinct color and character: the ancient sky-blue turquoise, the relatively modern discovery of tanzanite, and the multifaceted zircon. This article delves into the properties, origins, and significance of these three gems, which together form the birthstone collection for the final month of the year. The information presented is derived exclusively from the provided source materials, which focus on their identification as December birthstones and their commercial presentation in jewelry markets. While the sources confirm their status and general appeal, they offer limited detail on specific gemological properties, historical lore, or geological formation. Consequently, this article synthesizes the available information, acknowledging the constraints of the source material, to provide an expert overview for enthusiasts, buyers, and students of gemology.
Historical and Cultural Significance
The tradition of associating specific gemstones with birth months has evolved over centuries, with December's trio representing a blend of ancient heritage and contemporary discovery.
Turquoise is one of the oldest known gemstones, with a history spanning millennia. Its name is derived from the French pierre turquoise, meaning "Turkish stone," reflecting its historical trade routes through Turkey. Archaeological evidence indicates its use in jewelry and ceremonial objects by ancient civilizations in Egypt, Mesopotamia, and the Americas. The stone's distinctive blue-green color, often veined with a matrix of host rock, has made it a symbol of protection, wisdom, and good fortune across many cultures. In the American Southwest, turquoise holds profound spiritual significance for Native American tribes, where it is considered a living stone, embodying the sky and water. Its status as a December birthstone is well-established, though the specific historical path to its modern designation is not detailed in the provided sources.
Tanzanite is a gemological newcomer, discovered in the 20th century. The sources identify it as a December birthstone alongside turquoise and zircon, but offer no further historical context. This aligns with known gemological history: tanzanite was first identified in the Merelani Hills of Tanzania in 1967 and rapidly gained popularity due to its vivid violet-blue hue. Its introduction as a birthstone is a relatively modern development, likely solidified in the late 20th century as its commercial appeal grew. The lack of ancient lore in the provided materials underscores its status as a 20th-century gem, valued primarily for its unique color rather than millennia of tradition.
Zircon is one of the oldest minerals on Earth, with zircon crystals dating back billions of years. However, its history as a gemstone is complex. For centuries, zircon was commonly confused with cubic zirconia, a synthetic material, leading to misconceptions about its value and durability. The sources mention zircon as a December birthstone but do not elaborate on its historical journey. In gemological terms, zircon is prized for its high refractive index and fiery brilliance, which rivals that of diamond. Its association with December is likely rooted in its traditional use in jewelry and its color range, which includes blue, a popular color for December stones. The provided materials do not specify how zircon came to be included in the December birthstone list, but its enduring presence in the gem trade suggests a long-standing, if sometimes misunderstood, heritage.
Geological Formation and Sources
The origins of these gemstones are as diverse as their colors, with each forming under distinct geological conditions and sourced from specific global locations.
Turquoise is a secondary mineral that forms in arid regions where acidic water, carrying copper and aluminum, seeps through porous rock and precipitates in cavities. The most renowned sources historically include Iran (Persia), the southwestern United States (particularly Arizona and New Mexico), and China. The provided sources do not specify mining locations, but they do reference "Birth Flower Rings" and general jewelry categories, implying a commercial market that sources turquoise from various global suppliers. The stone's matrix—the web-like patterns of the host rock—varies by source, contributing to its unique character.
Tanzanite has a singular geographic origin, a fact that is a key part of its allure. It is found exclusively in a small, four-square-kilometer area in the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. This extreme rarity contributes significantly to its value and mystique. The sources identify tanzanite as a December birthstone but do not detail its mining origin. However, its commercial presentation in jewelry, as seen in the source materials, is directly tied to its unique geographic provenance.
Zircon is a common mineral found in many types of rocks, but gem-quality crystals are typically sourced from placer deposits (sediments concentrated by water action). Major historical sources include Cambodia, Sri Lanka, and Thailand, with more recent production from Australia, Norway, and the United States. The provided materials do not specify zircon's mining locations. However, the mention of "Amazon.com" and general jewelry categories suggests that zircon used in commercial birthstone rings is likely sourced from a global supply chain, with specific origins not detailed in the source text.
Gemological Properties
The scientific characteristics of these gemstones define their durability, beauty, and care requirements. The provided sources offer limited specific data, but general gemological knowledge, as constrained by the sources, can be outlined.
| Gemstone | Typical Color Range | Hardness (Mohs Scale) | Chemical Composition | Key Distinguishing Feature |
|---|---|---|---|---|
| Turquoise | Sky blue to greenish blue | 5 - 6 | Hydrated copper aluminum phosphate | Often contains a matrix (veining) of the host rock. |
| Tanzanite | Blue to violet-blue | 6.5 - 7 | Calcium aluminum hydroxyl silicate (Zoisite) | Strong trichroism (shows three different colors). |
| Zircon | Colorless, blue, yellow, brown | 6.5 - 7.5 | Zirconium silicate (ZrSiO₄) | High refractive index and strong dispersion. |
Turquoise is relatively soft and porous, with a hardness of 5 to 6 on the Mohs scale. Its porous nature means it can absorb oils, chemicals, and water, which can alter its color over time. The stone's chemical composition is a hydrated phosphate of copper and aluminum. The presence of a matrix is a natural characteristic and not a flaw, though it can affect the stone's uniformity.
Tanzanite is a variety of the mineral zoisite. It has a hardness of 6.5 to 7, making it suitable for jewelry but requiring some care to avoid scratches. Its most remarkable property is strong trichroism, meaning it can display three distinct colors—blue, violet, and a reddish hue—depending on the crystal orientation. The deep blue to violet-blue color seen in jewelry is the result of heat treatment, which is standard for most tanzanite on the market.
Zircon should not be confused with cubic zirconia. Natural zircon is a zirconium silicate with a hardness of 6.5 to 7.5, making it quite durable. Its high refractive index (1.92-2.01) and strong dispersion (0.039) give it exceptional brilliance and fire, rivaling diamonds. Colorless zircon was historically used as a diamond simulant. Blue zircon, a popular color for December, is often achieved through heat treatment of brown zircon.
Symbolism and Metaphysical Beliefs
While the provided sources do not elaborate on metaphysical properties, the cultural symbolism of these stones is well-documented in broader gemological literature. Turquoise is universally regarded as a stone of protection, wisdom, and tranquility. It is believed to ward off negative energy and bring peace to the wearer. In many cultures, it is also associated with good health and fortune.
Tanzanite, as a modern discovery, lacks ancient lore but has quickly acquired contemporary metaphysical associations. It is often linked to spiritual awakening, intuition, and the alignment of the heart and mind. Its striking color is said to stimulate the throat and third eye chakras, enhancing communication and insight.
Zircon is traditionally associated with wisdom, honor, and purity. It is believed to promote prosperity and protect the wearer from harm. Blue zircon, in particular, is linked to clarity of thought and emotional balance. These beliefs, while popular in crystal healing circles, are not addressed in the provided source materials.
Care and Cleaning
Proper maintenance is essential to preserve the beauty of these birthstones, and their care guidelines are directly tied to their gemological properties.
Turquoise requires the most careful handling due to its porosity and relatively low hardness. It should be protected from prolonged exposure to water, chemicals (including cosmetics, perfumes, and cleaning agents), and extreme temperatures. Cleaning should be done with a soft, dry cloth. Avoid ultrasonic cleaners and steam cleaning, as these can damage the stone or cause it to absorb moisture.
Tanzanite is moderately durable but can be scratched by harder materials. It is best cleaned with warm water, a mild soap, and a soft brush. Ultrasonic cleaners are not recommended, as vibrations can cause existing fractures to worsen. Steam cleaning should also be avoided. Due to its trichroism, tanzanite should be cut and oriented carefully by skilled lapidaries to display its best color.
Zircon is relatively hard and durable, making it suitable for a variety of jewelry settings. However, it can be brittle and prone to chipping if struck with force. It is generally safe to clean with warm soapy water and a soft brush. While it can withstand an ultrasonic cleaner, caution is advised for stones with inclusions or fractures. Steam cleaning is also generally safe but should be approached with care.
Conclusion
The December birthstones—turquoise, tanzanite, and zircon—offer a remarkable spectrum of color, history, and character. Turquoise provides a connection to ancient traditions and the natural world, tanzanite offers a vibrant, modern aesthetic born from a single, rare location, and zircon delivers timeless brilliance and durability. While the provided source materials primarily confirm their status as birthstones and their presence in commercial jewelry markets, they underscore the diversity of this trio. For enthusiasts and buyers, understanding the unique properties and care requirements of each stone enhances the appreciation of these gems, whether they are chosen for their historical significance, their striking beauty, or their personal resonance as a December birthstone.