For those born in the final month of the year, the birthstone selection is uniquely abundant and visually captivating. December is represented not by a single gem, but by a trio of stunning blue stones: Turquoise, Tanzanite, and Zircon. These gems, often referred to as the "blue trio," share a color palette that evokes the cool, clear skies of winter, yet each possesses a distinct history, geological origin, and set of properties. This guide provides an in-depth exploration of these three official December birthstones, along with a notable alternative, Blue Topaz, delving into their geological formation, gemological characteristics, historical lore, and their journey to becoming the cherished symbols for those born in December.
History and Lore: A Journey Through Time
The story of December's birthstones is one of both ancient tradition and modern discovery. Each stone carries a rich narrative woven through centuries of human culture.
Turquoise: The Ancient Talisman
Turquoise stands as one of the oldest known gemstones, prized for millennia across numerous civilizations. Its name offers a clue to its historic trade routes; "Turquoise" derives from the French phrase pierre turquoise, meaning "stone of Turkey." This nomenclature arose because the gem was first brought to Europe from Turkish bazaars, having originated in Persia and the Sinai Peninsula. From the earliest times, Turquoise was a favored gem for amulets, valued for its relative ease of being cut into various shapes and inscribed upon.
Ancient cultures imbued Turquoise with profound protective powers. It was believed to safeguard its wearer against danger and bring good fortune. This belief was so strong that in Tibet, the gem was considered a birthstone of fortune, health, and success, and was even used as a form of currency. Among the Incas and Mayas, Turquoise was offered as a gift to the gods. In the American Southwest, Native American tribes associated the stone with youth and strength. Beyond general protection, Turquoise was also a gem cherished by lovers and married couples, thought to protect relationships and preserve friendship if given as a gift. A unique attribute attributed to it was its ability to warn of approaching illness or danger by becoming pale. Its use in ancient Egyptian pharaohs' burial masks further underscores its status as a stone of power and prestige.
Tanzanite: The Modern Marvel
In stark contrast to Turquoise's ancient lineage, Tanzanite is the newest addition to the birthstone calendar. This striking violet-blue gemstone was discovered in 1967 in Tanzania, a location that inspired its name. Geologically, it is a variety of the mineral zoisite. Its discovery in a single, small area near Mount Kilimanjaro makes it one of the rarest gemstones in the world. This extreme rarity, coupled with its captivating color, has quickly elevated its status in the gemological world.
Zircon and Blue Topaz: The Evolving List
The history of December's birthstone list itself is a story of evolution. In 1912, the National Association of Jewelers in the United States standardized the unofficial birthstone list to create a practical and commercially viable selection for the jewelry industry. This list was later updated. In 1952, the Jewelry Industry Council of America added Zircon to December's offerings, and in 2002, Tanzanite was officially included. The reason for December having four recognized birthstones (including the popular alternative, Blue Topaz) is not definitively known, though some sources suggest it was to provide more affordable options for consumers.
Geological Formation and Sources
Understanding the origin of these gems reveals the unique geological processes that create their distinct colors and properties.
Turquoise
Turquoise is an opaque, hydrous phosphate of copper and aluminum. It is formed when groundwater containing copper seeps into bedrock. Over time, reactions with aluminum-rich minerals create the turquoise mineral. The presence of copper dictates the blue hues, while traces of iron can produce greenish tones. The dark lines and shapes often seen within turquoise are known as "matrix," which is the remnants of the surrounding host rock embedded within the gem.
Tanzanite
As a variety of zoisite, Tanzanite's formation is linked to a unique geological event. It is found only in a specific region of Tanzania, near the iconic Mount Kilimanjaro. This highly localized occurrence is the primary reason for its rarity. Its remarkable trichroism—the ability to appear in three different colors (blue, purple, and burgundy) depending on the viewing angle—is one of its most defining gemological features.
Zircon
Zircon is a mineral composed of zirconium silicate. It is one of the oldest minerals on Earth, with some specimens dating back billions of years. While zircon occurs in a variety of colors, the blue variety is the one designated for December. It is important to distinguish natural blue zircon from the synthetic material used in industrial applications. Natural blue zircon often derives its color from heat treatment of brownish zircon, a common and accepted practice in the gem trade.
Blue Topaz
Blue Topaz serves as a popular alternative December birthstone. Its exact historical origin is obscure, but it has been found throughout history. Today, it is mined in several countries, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States. Its significance is highlighted by its designation as the official state gem of Texas. Like zircon, much of the blue topaz seen in the market is the result of treating colorless or pale topaz with irradiation and heat to achieve its vibrant blue color.
Gemological Properties
The physical and chemical characteristics of the December birthstones are crucial for identifying them and determining their suitability for jewelry.
A Comparative Overview
While all three primary December stones are blue, their hardness, clarity, and structure differ significantly. The following table summarizes their key gemological properties based on information from the provided sources.
| Gemstone | Mineral Family | Chemical Formula | Typical Color(s) | Mohs Hardness | Key Optical Feature |
|---|---|---|---|---|---|
| Turquoise | Phosphate | Hydrous copper aluminum phosphate | Robin's-egg blue to green-blue | 5 - 6 | Opaque, often contains matrix |
| Tanzanite | Zoisite (Sorosilicate) | Ca2Al3(SiO4)3(OH) | Violet-blue, blue, purple | 6 - 7 | Strong Trichroism |
| Zircon | Zirconium Silicate | ZrSiO4 | Blue (often from heat treatment) | 6.5 - 7.5 | High refractive index, brilliance |
| Blue Topaz | Topaz (Silicate) | Al2SiO4(F,OH)2 | Various shades of blue | 8 | High durability, clarity |
Detailed Properties
Turquoise is the softest of the group, with a Mohs hardness ranging from 5 to 6. Its opacity is a defining characteristic, and its color can range from the highly prized "robin's-egg blue" to various shades of green-blue. The presence and pattern of the matrix are often used to evaluate its quality and authenticity.
Tanzanite has a hardness of 6 to 7 on the Mohs scale, making it suitable for most jewelry, though it requires some care to avoid sharp blows. Its most celebrated property is its trichroism, which gives it a dynamic visual appeal, shifting between vibrant blue, deep purple, and reddish-burgundy. This feature, combined with its rarity, makes it highly valued.
Zircon is known for its exceptional brilliance and fire, a result of its high refractive index. It is harder than both Turquoise and Tanzanite, with a Mohs hardness of 6.5 to 7.5. The blue variety is typically heat-treated to achieve its color, which is considered stable. It should not be confused with the synthetic cubic zirconia, which is a completely different material.
Blue Topaz is the most durable of all December birthstones. With a Mohs hardness of 8, it is highly resistant to scratching and wear, making it an excellent choice for everyday jewelry like rings and bracelets. It is typically found as a transparent gem with excellent clarity.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, the December birthstones have been attributed with powerful symbolic meanings and metaphysical properties.
The "blue trio" collectively symbolizes wisdom, protection, and spiritual growth. They are seen as stones that promote clarity of thought and a calm, serene state of mind.
Turquoise is perhaps the most storied in its metaphysical claims. It is widely regarded as a stone of protection, said to guard against negative energy and physical harm. It is also associated with good fortune, success, and happiness. As a gift, it is believed to foster friendship and preserve love. Its connection to spiritual grounding is strong, with traditions holding that it can alert its wearer to impending danger or illness by changing its color.
Tanzanite, as a modern discovery, has quickly accrued its own lore. It is associated with transformation and higher consciousness. Its trichroic nature is seen as symbolic of bridging the mind and the heart, encouraging a balanced perspective and spiritual awakening. It is considered a stone of purpose, helping individuals to move forward with clarity and determination.
Zircon is associated with purity, integrity, and honor. It is believed to aid in sleep and promote prosperity. Historically, it was also thought to ward off evil spirits and bring wisdom to its wearer.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones. The differences in their hardness and stability dictate the best practices for cleaning and storage.
Turquoise Care
Due to its relatively low hardness (5-6) and porous nature, Turquoise requires gentle handling. It is susceptible to damage from chemicals, including cosmetics, perfumes, and even skin oils, which can cause discoloration over time. To clean it, use warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. It is best to store Turquoise separately to prevent it from being scratched by harder materials.
Tanzanite Care
With a hardness of 6-7, Tanzanite is more durable than Turquoise but still demands care. It is susceptible to chipping or breaking if subjected to sharp impacts. It should not be worn during activities that could cause physical trauma to the stone. Cleaning can be done with warm, soapy water and a soft brush. As with Turquoise, avoid ultrasonic and steam cleaning, as the vibrations and heat can potentially damage the stone.
Zircon Care
Zircon is relatively hard (6.5-7.5) but can be brittle due to its crystal structure. It is important to protect it from hard knocks. Some zircon, particularly older stones, may have been subjected to heat treatment that could be reversed by strong vibrations or extreme temperature changes, so it is wise to avoid ultrasonic cleaners. The safest method for cleaning Zircon is with warm, soapy water and a soft brush.
Blue Topaz Care
As the most durable of the group with a hardness of 8, Blue Topaz is well-suited for everyday wear. It is less prone to scratching and damage. However, it can be sensitive to sudden temperature changes, which might cause fractures in stones with inclusions. Cleaning is straightforward: warm water, a small amount of mild soap, and a soft brush will restore its brilliance. It is generally safe to use an ultrasonic cleaner, but it is always prudent to be cautious.
Conclusion
The birthstones for December offer a remarkable diversity of choice, united by the serene and beautiful color of blue. From the ancient protective talisman of Turquoise to the rare, trichroic brilliance of Tanzanite and the fiery sparkle of Zircon, each gem provides a unique connection to the natural world and human history. The addition of the highly durable Blue Topaz as an alternative further expands the options for those born in this month. This rich selection ensures that every December-born individual can find a gemstone that not only represents their birth month but also resonates with their personal style and story.