The month of December is uniquely associated with three distinct gemstones: turquoise, tanzanite, and zircon. This trio offers a diverse palette of blue hues, from the opaque, sky-like tones of turquoise to the vivid violet-blue of tanzanite and the brilliant fire of zircon. Each stone carries its own geological story, historical significance, and set of gemological properties. As birthstones, they provide December-born individuals with a choice that reflects personal style, from the rustic charm of turquoise to the modern elegance of tanzanite. This article explores the origins, characteristics, and lore of these three December birthstones, drawing upon authoritative sources to provide a comprehensive guide for gemstone enthusiasts and jewelry buyers.
History and Lore
The historical journey of these three stones to their status as December birthstones is marked by tradition, discovery, and modern standardization. Turquoise holds the oldest claim, with a history stretching back millennia. Archaeological evidence indicates that Native Americans in the Southwestern United States utilized turquoise over 2,000 years ago, creating beads, pendants, and inlay work. This deep-rooted cultural connection continues today, as turquoise remains an important part of Southwestern culture. Its symbolic power is also long-standing; traditional beliefs regard turquoise as a love charm, a symbol of good fortune and success, and a protective talisman against harm. Turquoise rings, in particular, were thought to ward off evil spirits, and the stone was believed to relax the mind.
Zircon's path to becoming a December birthstone is more recent. It replaced lapis lazuli as a modern birthstone in 1952. Historically, zircon was valued for its high luster and colorful fire, which is similar to that of a diamond. Because of these optical properties, zircon was once used as a diamond alternative. Its ability to provide a wide range of colors, from yellow and red to brown in its natural state, made it appealing, though most of the blue zircon seen today is the result of treatment.
Tanzanite is the newest member of the December birthstone family. Its discovery is a relatively modern event, and its inclusion in birthstone lists is recent. The stone's defining characteristic—its color shift depending on the angle of viewing—has contributed to its rapid rise in popularity. Most tanzanite sold in jewelry today exhibits a blue to bluish purple to bluish violet color, a hue typically achieved through heat treatment of the raw material.
Geological Formation and Sources
The formation and mining locations of these gemstones are as varied as their appearances. Turquoise forms in arid regions where acidic, copper-rich waters percolate through rocks containing aluminum and phosphorus. The Southwestern United States is a significant source, with a history of Native American use. However, turquoise is also mined around the world, contributing to its availability in the jewelry market.
Zircon is a mineral that forms in igneous and metamorphic rocks. While natural zircons can be found in a variety of colors, the gemological market often sees them transformed through treatment. The process of heat and irradiation can change the color of most natural yellow, red, or brown zircons into the popular blue, green, and other colors. Today, approximately 80% of the zircons sold are blue, with this color being produced by treatment.
Tanzanite's origin is geographically specific. It is mined in Tanzania, East Africa, which gives the stone its name. The geological conditions that created tanzanite are unique to this region, making it a relatively rare gemstone. Its formation is linked to the same tectonic activity that formed Mount Kilimanjaro and the Great Rift Valley. The stones are often heated to enhance their blue-to-violet color, a standard practice in the gem trade.
Gemological Properties
Understanding the physical and optical properties of these stones is crucial for appreciating their value and for proper care. The following table summarizes key gemological data derived from the provided sources.
| Property | Turquoise | Zircon | Tanzanite |
|---|---|---|---|
| Color | Blue to blue-green to yellowish green; bright blue is most preferred. | Naturally yellow, red, or brown; commonly treated to blue, green, and other colors. | Blue to bluish purple to bluish violet; exhibits color change. |
| Luster | N/A | Bright, high luster. | N/A |
| Clarity/Cleavage | Opaque. | Prone to breakage. | Has perfect cleavage and will break easily. |
| Hardness (Mohs) | Low hardness, easily scratched. | Prone to breakage (implied lower toughness). | N/A |
| Cut | Usually cut into cabochon shapes, often freeform. | N/A | N/A |
| Treatment | N/A | Heat and irradiation are used to produce blue and other colors. | Heat treatment is used to produce the blue to bluish violet color. |
| Chemical Formula | N/A | N/A | N/A |
Note: The sources do not provide specific hardness measurements (Mohs scale), chemical formulas, or refractive indices. The properties listed are those explicitly mentioned.
Turquoise is an opaque mineral, which dictates its use in jewelry. It is typically cut into cabochons, often in freeform shapes to maximize the use of the rough material. Its low hardness makes it susceptible to scratching, and its composition requires careful handling.
Zircon is known for its high luster and fire, which can rival that of diamond. However, the sources note that zircon is "prone to breakage," indicating lower toughness despite its potential hardness. Most of the zircon on the market has undergone treatment to achieve its desirable colors.
Tanzanite is characterized by its pleochroism—the color shift when viewed from different angles. This property, combined with its vivid hue, makes it a unique gemstone. The sources highlight that it has "perfect cleavage and will break easily," which is a critical consideration for jewelers and owners. Like zircon, the color of most commercial tanzanite is the result of heat treatment.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, each of the December birthstones carries a legacy of symbolic meaning and metaphysical belief. Turquoise is rich in symbolism, regarded traditionally as a love charm and a symbol of good fortune and success. It is believed to have a calming effect on the mind and to offer protection from harm, with turquoise rings specifically thought to repel evil spirits.
Zircon, while historically used as a diamond simulant, is also associated with specific attributes. The sources mention that zircon was believed to have protective properties, though the primary focus in the provided materials is on its optical qualities and its role as a birthstone.
Tanzanite's metaphysical beliefs are not detailed in the provided chunks. The sources focus on its geological origin, color properties, and status as a modern birthstone. Any claims about its symbolic meaning would be speculative without direct support from the provided materials.
Care and Cleaning
The care for these gemstones is directly tied to their gemological properties. Turquoise, with its low hardness and opaque nature, is best set in protective jewelry settings like sterling silver. It should be cleaned with a soft, damp cloth and stored separately from harder stones to avoid scratches. Harsh chemicals and ultrasonic cleaners should be avoided.
Zircon, being prone to breakage, requires careful handling. It should be protected from sharp blows and extreme temperature changes, which can cause fracturing. Cleaning should be done with warm soapy water and a soft brush, avoiding any mechanical stress.
Tanzanite is particularly delicate due to its perfect cleavage. It is susceptible to breaking from a hard impact. Owners should remove tanzanite jewelry before engaging in physical activities. Cleaning should be gentle, using only warm soapy water and a soft brush. Ultrasonic and steam cleaners are not recommended for tanzanite, as the vibrations and heat can cause internal fractures.
Conclusion
The December birthstones—turquoise, tanzanite, and zircon—offer a remarkable spectrum of the color blue, each with a distinct character and history. Turquoise connects us to ancient cultures and the earth, with its opaque, sky-like hues and long-standing protective symbolism. Zircon provides a brilliant, fiery alternative with a rich history as a diamond simulant, now primarily available in treated blue shades. Tanzanite, the newest addition, captivates with its unique color-shift phenomenon and rare geographic origin. Together, they provide December-born individuals with a choice that spans from the traditional to the contemporary. Understanding their origins, properties, and care requirements allows for a deeper appreciation of these beautiful gemstones, ensuring they can be enjoyed for generations to come.