The final month of the year is uniquely represented by a trio of birthstones: turquoise, zircon, and tanzanite. Each gem offers a distinct shade of blue, from the sky-like hues of turquoise to the fiery sparkle of zircon and the violet-blue allure of tanzanite. This diversity allows December-born individuals to select a stone that perfectly matches their personal style. While turquoise boasts one of the oldest histories in gemology, zircon provides a brilliant, diamond-like alternative, and tanzanite is a relatively recent addition to the birthstone family, celebrated for its captivating color. This article delves into the geological origins, gemological properties, historical significance, and cultural symbolism of these three remarkable December birthstones, providing a comprehensive guide for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
The history of these three December birthstones spans millennia, with turquoise holding the most ancient legacy.
Turquoise has been used as a gemstone for thousands of years. In the southwestern United States, Native Americans were using turquoise over 2000 years ago. Ancient artists in this region produced beads, pendants, inlay work, and small sculptures from the stone. To this day, turquoise remains an important part of Southwestern culture. Its journey to becoming a modern birthstone is part of a longer evolution. The concept of birthstones traces back to the Breastplate of Aaron, a ceremonial garment described in the Old Testament, which held twelve gemstones representing the twelve tribes of Israel. Over time, these stones became associated with zodiac signs and eventually calendar months. The first official birthstone chart in the United States was established by the National Association of Jewelers (now Jewelers of America), creating a standardized list. While the specific date for turquoise's official inclusion as a December birthstone is not provided in the sources, it is listed as a traditional and modern birthstone in comprehensive charts.
Zircon is another gem that serves as a birthstone for December. It is a bright gem with high luster, and many specimens produce a colorful fire that is similar to diamond. Its inclusion in birthstone lists is more recent. The birthstone chart received its first significant revision, adding alexandrite to June, citrine to November, and pink tourmaline to October as alternative options. Later, the American Gem Trade Association added tanzanite as a December birthstone, marking the first change to the list in 50 years. Zircon is also listed as a modern birthstone for December, often appearing in blue shades. Sources indicate that spinel, citrine, and tanzanite are recent modern additions, and the modern list for December includes blue zircon, blue topaz, and tanzanite. The traditional list for December includes turquoise and lapis lazuli.
Tanzanite is the newest of the three, having been added to the official birthstone list relatively recently. The American Gem Trade Association added tanzanite as a December birthstone, marking the first change to the list in 50 years. This addition reflects a trend of updating birthstone lists to include newly discovered or newly popularized gems. While its history is short in the context of gemology, its impact has been significant, offering a new, vibrant blue option for December.
Geological Formation and Sources
Understanding where these gems are found and how they form is key to appreciating their value and characteristics.
Turquoise is a blue to blue-green to yellowish green mineral. While specific mining locations for turquoise are not detailed in the provided sources, it is noted that turquoise jewelry is mined around the world. The stone's formation is linked to its geological context, but the sources do not elaborate on the specific processes. Its presence in the southwestern United States for over two millennia suggests a long-standing geological source in that region.
Zircon is mined around the world. The sources do not specify particular countries or mining regions for zircon, but they confirm its global distribution. Zircon is a bright gem with high luster, and its formation is part of the broader geological processes that create many crystalline minerals.
Tanzanite is also mined around the world. Like zircon, the specific locations are not detailed in the provided chunks, but its global mining presence is confirmed. The addition of tanzanite to the birthstone list is a testament to the ongoing discovery of gemstone sources worldwide. The formation of tanzanite is linked to specific geological conditions, though the sources do not provide details on its genesis.
Gemological Properties
The physical and optical properties of a gemstone determine its durability, appearance, and value. The following table summarizes key gemological properties for the December birthstones based on the provided sources.
| Gemstone | Color | Hardness (Mohs Scale) | Key Characteristics | Notes on Durability |
|---|---|---|---|---|
| Turquoise | Blue to blue-green to yellowish green | Low hardness | Opaque, often cut into cabochons | Prone to scratching due to low hardness. |
| Zircon | Bright, with colorful fire similar to diamond | Not specified in sources | High luster, bright gem | Prone to breakage. |
| Tanzanite | Blue to purple | 6.5-7 | Prone to breakage, has perfect cleavage | Will break easily if struck. |
Turquoise is an opaque mineral, which is why it is usually cut into cabochon shapes, often freeform to take full advantage of the rough, instead of being cut into calibrated shapes and sizes. Bright blue turquoise is the most preferred color. Its hardness is described as "low," which makes it easily scratched. This property dictates its care and setting, often in protective jewelry settings.
Zircon is noted for its high luster and the colorful fire it produces, which is similar to a diamond's brilliance. While its exact hardness is not specified in the sources, it is listed as a gem that is "prone to breakage." This suggests it requires careful handling, similar to other gemstones with specific cleavage or fragility.
Tanzanite has a hardness of 6.5 to 7 on the Mohs scale. More importantly, it has perfect cleavage, which means it will break easily if struck with force. This property is critical for jewelry design and wear, as it requires protective settings and careful handling to avoid damage from impacts.
The sources also provide broader context on birthstone durability. For instance, emerald, opal, peridot, and zircon are all noted as being prone to breakage. Moonstone, topaz, and tanzanite all have perfect cleavage and will break easily. Pearl, opal, and turquoise all have a low hardness and are easily scratched. This information underscores the importance of understanding a gemstone's physical properties for both jewelers and consumers.
Symbolism and Metaphysical Beliefs
Gemstones have been imbued with symbolic meaning and metaphysical beliefs for centuries. While these beliefs are not scientifically proven, they are a significant part of the cultural history of gemstones.
Turquoise is deeply embedded in Southwestern culture, where it has been used for over two millennia. Its cultural significance is tied to the art and spiritual practices of Native American tribes in the region. The sources do not elaborate on specific metaphysical beliefs for turquoise beyond its cultural importance.
Zircon is not described with specific symbolism or metaphysical properties in the provided sources. Its primary description is based on its visual properties—its brightness and fire.
Tanzanite is also not described with specific symbolism in the provided sources. Its addition to the birthstone list is presented as a modern update to provide more color options.
For a broader context on birthstone symbolism, the sources indicate that each month's stones have associated meanings. For example, aquamarine evokes blue skies and calming waters, while bloodstone represents health and strength. Garnet symbolizes many different positive emotions. Amethyst is said to cure drunkenness and make you quick-witted in business. Diamond represents love, purity, and strength. Emerald symbolizes rebirth, love, and wisdom. Ruby represents passion, protection, and prosperity. Sapphire is the birthstone of wisdom, loyalty, and nobility. Opal and tourmaline are believed to have been created from rainbows. Topaz and citrine are known for their calming energies. The symbolism for December's trio—turquoise, tanzanite, and zircon—is not specified in the provided materials, but they are part of a rich tradition of assigning meaning to gemstones.
Care and Cleaning
Proper care is essential for maintaining the beauty and longevity of gemstone jewelry, especially given the varying durability of these stones.
Turquoise, with its low hardness, is easily scratched. It should be protected from abrasive materials and harsh chemicals. Cleaning should be gentle, using a soft, damp cloth and avoiding ultrasonic cleaners or steam, which could damage the stone or any treatments it may have undergone. Given its opacity and common use in cabochon settings, it is often set in protective mounts.
Zircon is prone to breakage. While the sources do not specify cleaning methods, gemstones with such fragility should be handled with care. They are best cleaned with warm, soapy water and a soft brush, avoiding sudden temperature changes and impacts. Jewelry settings should protect the stone from knocks.
Tanzanite has perfect cleavage, making it very susceptible to breaking from impact. It requires careful handling and protective settings. Cleaning should be done with warm, soapy water and a soft cloth. Ultrasonic cleaners and steam are not recommended, as the vibrations and heat can cause the stone to fracture. It is advisable to remove tanzanite jewelry during activities where it could be struck.
For all gemstones, the sources emphasize the importance of disclosure. When purchasing birthstone jewelry, it is crucial to know whether the stones are natural, lab-created, or simulants. The Federal Trade Commission requires clear disclosure of man-made gems. Lab-created and imitation gems are often used to reduce costs and improve size, color, and clarity, but they must be clearly labeled as such. This ensures that consumers can make informed decisions based on their preferences for natural versus synthetic materials.
Conclusion
The December birthstones—turquoise, zircon, and tanzanite—offer a captivating spectrum of blue, each with its own unique history and properties. Turquoise carries the weight of ancient tradition, with a usage history spanning over two millennia in the southwestern United States and a deep cultural significance. Zircon provides a brilliant, diamond-like fire, serving as a durable and sparkling alternative. Tanzanite, a modern addition to the birthstone family, captivates with its unique violet-blue hue and is celebrated for its recent inclusion on official lists. Understanding their geological origins, gemological properties, and care requirements is essential for both appreciation and preservation. As with all gemstones, informed purchasing, including awareness of natural versus lab-created options, ensures that the beauty and significance of these December gems can be enjoyed for generations. Together, they represent a rich tapestry of geological wonder, historical legacy, and personal expression for those born in the final month of the year.