December is a unique month in the gemological calendar, distinguished by its designation of four distinct birthstones. While many months possess a single traditional gem, December offers a quartet of options: Turquoise, Zircon, Tanzanite, and Blue Topaz. This abundance provides individuals born in the final month of the year with a wide spectrum of choices, ranging from ancient, opaque stones to modern, brilliantly faceted gems. These stones are united by a predominant color palette of captivating blues, though they vary significantly in origin, composition, history, and physical properties.
The selection of these specific gemstones reflects a blend of deep historical tradition and modern market adaptation. Turquoise stands as the ancient anchor, a stone revered for millennia. Zircon offers a historical alternative with a fiery brilliance. Tanzanite represents a relatively recent discovery, bringing a unique violet-blue hue to the collection. Finally, Blue Topaz, treated to achieve its vibrant color, has become a popular and accessible choice for contemporary jewelry. This article will explore each of these four gems in detail, examining their geological formation, gemological characteristics, historical lore, and their journey to becoming the celebrated birthstones of December.
Turquoise: The Ancient Sky-Stone
Turquoise is arguably the oldest and most historically significant of the December birthstones. Its name derives from the French phrase pierre tourques, or "Turkish stone," reflecting its introduction to Europe through Turkey from Persian sources. For thousands of years, this opaque, sky-blue to greenish-blue mineral has been a symbol of wealth, protection, and status across numerous civilizations.
History and Lore The historical record of Turquoise use is extensive. Sources indicate it was cherished by royalty as far back as ancient Egypt, where it was used to create intricate jewelry and funerary ornaments for figures like King Tutankhamun. The gemstone was also highly valued in ancient Persia and by the indigenous peoples of the Americas. A consistent theme in the lore surrounding Turquoise is its purported protective power. It was believed to safeguard the wearer from harm, including preventing falls and deflecting negative energy. Beyond physical protection, it was also associated with wisdom, tranquility, and friendship. The Gregorian birthstone poem for December specifically mentions this gem, advising, "If cold December gave you birth, / The month of snow and ice and mirth, / Place on your hand a turquoise blue; / Success will bless whate'er you do." This verse encapsulates the long-held belief in the stone's ability to bring good fortune and success.
Geological Formation and Sources Turquoise is a secondary mineral that forms in arid regions where acidic, copper-rich groundwater percolates through aluminum-bearing rocks. Over geological time, this process creates nodules and veins of the mineral. The most significant sources are located in the Southwestern United States (particularly Arizona and New Mexico), Iran, Egypt, China, Mexico, and parts of Central Asia and Africa. A distinctive feature of many Turquoise specimens is the presence of a "matrix," which is the remnant of the host rock in which the stone formed. This matrix often appears as a fine, dark, spiderweb-like network within the blue stone, adding to its unique character.
Gemological Properties As a mineral, Turquoise is relatively soft and porous, which dictates how it must be cared for. It ranks between 5 and 6 on the Mohs Hardness Scale, making it susceptible to scratching and damage from hard impacts. Its porosity also means it can be discolored by chemicals, oils, and even the natural oils from skin contact. Because of these properties, Turquoise jewelry requires careful handling. It is often stabilized or treated to enhance its durability and color, but collectors and wearers should be aware of its delicate nature.
Zircon: The Fiery Alternative
Zircon is one of the oldest minerals on Earth, yet it remains a somewhat underappreciated gem in the modern jewelry market. It is frequently confused with the synthetic cubic zirconia, a completely different material, but natural Zircon possesses a brilliance and fire that is entirely its own. It has a long history as a traditional December birthstone and continues to be a popular choice, particularly in the United States.
History and Lore Zircon has served as a December birthstone for centuries, appearing on historical lists long before the modern standardized charts. It was a traditional alternative to Lapis Lazuli and, according to one source, replaced Lapis Lazuli on the U.S. birthstone list in 1952. Throughout history, Zircon has been associated with various protective and spiritual qualities. It was believed to promote honor and prosperity in the wearer and to help induce sleep. Its brilliance was often linked to the sparkle of stars, and it was thought to guide travelers through the night.
Geological Formation and Sources Zircon is a zirconium silicate mineral found in igneous, metamorphic, and sedimentary rocks. It is a durable mineral that is resistant to weathering, which is why it is often found in riverbeds and as alluvial deposits. Major sources for gem-quality Zircon include Thailand, Cambodia, Sri Lanka, and Australia. The stone's durability makes it suitable for jewelry, though it can be brittle.
Gemological Properties Zircon is known for its exceptional refractive index, which is higher than that of a diamond, giving it a remarkable brilliance and fire. It also exhibits strong birefringence (double refraction), a property that can sometimes be observed with the naked eye, causing facets to appear doubled. Zircon occurs in a variety of colors, but the blue variety is the one specifically associated with December. This blue color is often the result of heat treatment, which can transform brownish Zircon into the desirable blue hue. On the Mohs scale, Zircon has a hardness of 6.5 to 7.5, making it reasonably durable for jewelry, but its brittleness means it should be protected from sharp blows.
Tanzanite: The Modern Marvel
Tanzanite is the newest addition to the December birthstone family, having been discovered in the 20th century. Its introduction brought a fresh and vibrant option to the market, quickly gaining popularity for its unique color and compelling backstory. It was officially added as a modern birthstone for December in 2002.
History and Lore The story of Tanzanite is a modern gemological tale. It was discovered in the Merelani Hills of Tanzania in the late 1960s. The stone was brought to international prominence by the jewelry company Tiffany & Co., which recognized its beauty and unique violet-blue color and began featuring it in its collections in 1968. Due to its relative scarcity and single-source origin, it was marketed as a "gemstone of a generation." In terms of symbolism, Tanzanite is associated with transformation, intuition, and spiritual growth. It is believed to enhance emotional balance and is said to prevent depression, making it a stone of great significance for personal well-being.
Geological Formation and Sources Tanzanite is a variety of the mineral zoisite. Its formation is linked to a unique geological event that occurred roughly 585 million years ago, when intense heat and pressure altered the zoisite crystals in the region. This process is believed to have occurred only in a small, specific area of Tanzania, making the gemstone's origin exceptionally localized. To this day, Tanzania remains the only known source of Tanzanite in the world, a fact that contributes to its rarity and value.
Gemological Properties Tanzanite is celebrated for its dramatic trichroism, the ability to display three different colors when viewed from different crystallographic directions. It typically appears a deep blue when viewed down the Z-axis, a violet-red down the Y-axis, and a translucent brownish-yellow or grey down the X-axis. Most of the rough material is naturally brownish, and it is heated to temperatures of around 600-700°C to permanently induce the desirable blue and violet hues. With a hardness of 6.5 to 7 on the Mohs scale, it is softer than Zircon and Blue Topaz, requiring some care to avoid scratches and impacts.
Blue Topaz: The Vibrant Classic
Blue Topaz, with its brilliant, clear blue color, is a highly popular and accessible gemstone. While natural blue Topaz is rare, the vast majority of Topaz available on the market is treated to achieve its vivid color. It has become a staple in modern jewelry and is one of the most common December birthstones offered today.
History and Lore Historically, Topaz was often associated with yellow gemstones. The ancient Greeks believed it protected against injury and illness. However, the modern identification of Topaz as a blue gem has firmly placed it in the December category. The gem is believed to represent clarity of thought, love, and affection. Its bright, clear color is often linked to communication and emotional expression.
Geological Formation and Sources Topaz is a silicate mineral of fluorine and aluminum. It forms in igneous rocks, particularly in cavities within granites and rhyolites. While Topaz is found in many locations globally, including Brazil, Sri Lanka, and Nigeria, the sources for the material that is treated to become blue Topaz are widespread. The process of creating the blue color is what makes this gem so widely available.
Gemological Properties Colorless Topaz is the starting point for creating Blue Topaz. The pale yellow or colorless crystals are treated with heat and irradiation to produce the various shades of blue that are popular in the market. These treatments are stable and result in distinct shades, such as the light, sky-blue "Swiss Blue" and the deep, saturated "London Blue." Topaz is a relatively hard and durable gem, rating an 8 on the Mohs scale, making it an excellent choice for all types of jewelry, including rings and bracelets that are subject to daily wear. Its hardness and affordability, combined with its vibrant color, make it a favorite among jewelers and consumers.
Care and Cleaning for December Birthstones
Understanding the physical properties of these gems is essential for their long-term preservation. Each of the four December birthstones has unique care requirements based on its hardness, cleavage, and stability.
- Turquoise: As the softest and most porous of the group, Turquoise demands the most care. It should be cleaned with a soft, dry cloth. Avoid ultrasonic cleaners, steam, and any chemicals, including household cleaners, lotions, and perfumes. Store it separately to prevent scratching.
- Zircon: Although relatively hard, Zircon is brittle and can be easily chipped or abraded if knocked against a hard surface. It is best cleaned with warm soapy water and a soft brush. Avoid ultrasonic cleaners and extreme temperature changes, which can cause fractures.
- Tanzanite: With a hardness of 6.5 to 7, Tanzanite is suitable for pendants and earrings but requires caution in rings. It has perfect cleavage in one direction, meaning it can split if struck with force. Clean with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaning.
- Blue Topaz: The most durable of the four, Blue Topaz is relatively easy to care for. It can be cleaned with warm soapy water and a soft brush. While it is generally safe for ultrasonic cleaning, it is best to avoid harsh temperature changes. Be aware that some Topaz can be fracture-filled, in which case only gentle cleaning is recommended.
Conclusion
The birthstones of December offer a remarkable diversity that reflects the richness of the gem world itself. From the ancient, protective talisman of Turquoise to the fiery, star-like brilliance of Zircon, the modern, transformative allure of Tanzanite, and the vibrant, accessible clarity of Blue Topaz, each gem provides a unique narrative. They span geological time, from minerals formed in the dawn of Earth's history to those discovered in the 20th century. They cross cultures, from the royal tombs of Egypt to the markets of modern America. For those born in December, the choice is not merely one of color or style, but of connecting with a piece of history, science, and symbolism that is as deep and varied as the winter month itself.