For individuals born in the final month of the year, the birthstone options are as diverse and captivating as the winter season itself. December is uniquely associated with three distinct gemstones: Turquoise, Tanzanite, and Zircon. Each possesses a unique color palette, historical narrative, and set of gemological properties, offering a wide spectrum of choices for those seeking a personal connection to their birth month. While all are celebrated for their blue hues—a color often linked to calmness and wisdom—their origins, durability, and cultural significance vary dramatically. This article delves into the science, history, and lore of these three remarkable December birthstones, providing a comprehensive guide for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
The journey of these gemstones from ancient talismans to modern birthstones is a story of cultural evolution and standardization. The concept of birthstones is not a modern invention but has roots stretching back centuries, with connections to the biblical High Priest’s breastplate and ancient astrological systems. The modern birthstone chart, however, is a product of the 20th century.
Turquoise boasts the most ancient history of the three. It has been used as a gemstone for thousands of years, with evidence of its use in the Southwestern United States by Native Americans over 2000 years ago. There, it was not merely an ornament but a cultural cornerstone, used to create beads, pendants, inlay work, and small sculptures. This deep historical integration makes turquoise an enduring symbol of Southwestern heritage and artistry.
Zircon is one of the oldest minerals on Earth, with some crystals dating back billions of years. While its use as a gemstone is ancient, its role in the modern birthstone list is more recent. It was added to most official birthstone lists in 1952. At that time, topaz was a relatively costly gem, but the discovery of large deposits in Brazil subsequently reduced topaz's price. This shift allowed zircon to secure its place as a December birthstone, valued for its brilliance and fire.
Tanzanite is the newest addition to the December family. It was discovered in the 20th century and was officially added to the birthstone list by the American Gem Trade Association in 2002, marking the first change to the list in 50 years. Its inclusion reflects the dynamic nature of the gemstone market and the ongoing effort to provide modern, appealing options. While it lacks the ancient history of turquoise or zircon, its rapid ascent to prominence is a testament to its unique beauty and successful marketing.
The official standardization of birthstones in the United States began with the National Association of Jewelers (now Jewelers of America), which established the first official chart. Over the decades, this chart has been updated to include new discoveries and alternatives, such as adding alexandrite to June, citrine to November, and spinel to August. The current list for December, featuring turquoise, tanzanite, and zircon, represents a blend of traditional and modern preferences, allowing individuals to choose based on color, durability, or personal significance.
Geological Formation and Sources
The three December birthstones originate from vastly different geological environments, which influences their availability and physical characteristics.
Turquoise is a secondary mineral formed by the reaction of water carrying dissolved copper and aluminum with pre-existing rocks. It is typically found in arid regions where these conditions are met. The finest quality turquoise, known for its vibrant "robin's egg" blue, often comes from specific mines that have been historically significant. While sources are not detailed in the provided materials, the gemstone's global distribution is acknowledged, and it is noted that genuine turquoise is generally affordable, making it accessible to a wide audience. Lab-created turquoise is also available for cost-conscious shoppers.
Zircon is a mineral that forms in a variety of geological settings, including igneous and metamorphic rocks. It is a common accessory mineral in many rock types. The provided sources highlight that the discovery of large deposits in Brazil significantly impacted the market for topaz, indirectly affecting zircon's position. While specific mining locations for zircon are not listed, its presence in Brazil and other global locations is implied. It is a bright gem with high luster, and many specimens produce a colorful fire similar to that of a diamond.
Tanzanite has a very specific origin. It is found in only one place in the world: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This extreme rarity contributes to its value and appeal. The gemstone is a variety of the mineral zoisite and is known for its striking blue-to-violet color, which is often the result of heat treatment applied to the naturally brownish material. The sources do not provide details on its geological formation but confirm its unique and limited geographic source.
Gemological Properties
Understanding the physical and chemical properties of these gemstones is crucial for their selection, care, and valuation. The following table summarizes key gemological data for the December birthstones based on the provided sources.
| Gemstone | Color Range | Hardness (Mohs Scale) | Key Properties & Notes |
|---|---|---|---|
| Turquoise | Blue to blue-green to yellowish green | Low (Easily scratched) | Opaque; often cut into cabochons; prone to breakage; low hardness. |
| Zircon | Various, but often associated with blue for December | Not specified in sources | Bright gem with high luster; produces fire similar to a diamond; prone to breakage. |
| Tanzanite | Blue to purple | 6.5-7 | Has perfect cleavage and will break easily; often heat-treated. |
Color: Turquoise is prized for its blue to blue-green hues, with bright blue being the most preferred. Zircon, while available in many colors, is often presented in blue for December. Tanzanite is renowned for its unique blue-to-purple coloration, which can shift depending on the light and viewing angle.
Hardness and Durability: Durability is a critical factor for jewelry. The sources provide important warnings about the fragility of some birthstones. Turquoise has a low hardness and is easily scratched, which is why it is often set in protective settings and worn with care. Zircon is noted as being prone to breakage. Tanzanite is described as having "perfect cleavage," meaning it has planes of weakness along which it can split if struck with sufficient force. This makes it a gemstone that requires careful handling and protective jewelry settings, especially for rings or bracelets subject to impact.
Cut and Clarity: Due to its opaque nature, turquoise is typically cut into cabochons, often in freeform shapes to maximize the use of the rough material. Zircon, with its high luster and brilliance, is often faceted to enhance its fire. Tanzanite is also faceted to showcase its vivid color and clarity.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, these gemstones are rich in symbolic meaning and metaphysical lore, which has been part of their appeal for centuries.
Turquoise has long been associated with protection, healing, and wisdom. Its historical use by Native American cultures imbues it with deep spiritual significance, often linked to the sky and water. It is considered a stone of peace and tranquility.
Zircon is believed to promote honor, purity, and wisdom. Its brilliance is often associated with clarity of thought and purpose. Some traditions also link it to prosperity and protection.
Tanzanite, as a modern discovery, has quickly developed its own set of metaphysical associations. It is often described as a stone of transformation, intuition, and spiritual awakening. Its unique color and rarity contribute to its reputation as a gemstone that facilitates higher consciousness and calm.
It is important to note that while these metaphysical beliefs are widely circulated and add to the cultural richness of the stones, they are not recognized by scientific gemology. Their value in the market is primarily determined by the gemological properties discussed earlier.
Care and Cleaning
Proper care is essential to maintain the beauty and integrity of any gemstone, especially for those with lower hardness or perfect cleavage like the December birthstones.
Turquoise requires gentle care due to its low hardness. It should be protected from chemicals, perfumes, and cosmetics, which can damage its surface. Cleaning should be done with a soft, damp cloth; ultrasonic and steam cleaners are not recommended. It is best stored separately to avoid scratches from harder gems.
Zircon, while harder than turquoise, is brittle and prone to chipping. It should be handled with care to avoid hard impacts. Cleaning can be done with warm, soapy water and a soft brush, but avoid sudden temperature changes, which can cause fractures.
Tanzanite is the most delicate of the three in terms of cleavage. It should never be subjected to ultrasonic cleaners or steam, as the heat and vibrations can cause it to crack or break. Cleaning should be done gently with a soft brush, warm water, and mild soap. Due to its cleavage, it is not recommended for rings or bracelets that are worn daily, making it a better choice for earrings, pendants, or occasional-wear rings.
For all gemstones, it is advisable to have them inspected periodically by a professional jeweler to check for loose settings or damage, ensuring their longevity.
Conclusion
The birthstones for December—Turquoise, Tanzanite, and Zircon—offer a remarkable trio of choices, each with a distinct identity. Turquoise provides a connection to ancient history and earthy, opaque beauty. Zircon delivers exceptional brilliance and fire, with a legacy spanning billions of years. Tanzanite represents modern rarity and a captivating color spectrum found nowhere else. Their selection involves considering not only personal preference for color and style but also practical factors like durability and care requirements. Together, they encapsulate the diverse and enduring appeal of gemstones, serving as personal talismans that carry deep historical, cultural, and scientific significance for those born in the last month of the year.