The month of December is uniquely distinguished in the world of gemology by its association with not one, but four distinct birthstones: Turquoise, Tanzanite, Blue Topaz, and Zircon. This multiplicity offers a remarkable spectrum of colors, histories, and symbolic meanings, setting December apart from most other months in the traditional birthstone calendar. The official recognition of these four stones reflects both historical evolution and modern consumer demand for variety in color, durability, and price. While other months may have a single gemstone, December provides a small treasure chest of options, each capturing a different facet of the month’s icy beauty—from the ancient, earthy tones of turquoise to the vibrant, modern brilliance of blue topaz.
The journey to this expanded list is a story of tradition meeting commerce. Initially, turquoise and zircon were the primary stones associated with December. Over time, as the gem market grew and new discoveries were made, tanzanite joined the list, followed later by the popularized blue topaz. This expansion was driven by a desire to offer consumers more flexibility in style and budget, ensuring that every December-born individual could find a gemstone that resonates with their personal taste. The common thread among them is a cool, wintry palette, mirroring December’s skies and twilight blues. This article will delve into the rich history, geological origins, gemological properties, and cultural symbolism of each of these four remarkable stones, providing a comprehensive guide to the birthstones of December.
History and Lore: A Journey Through Time
The history of December’s birthstones spans millennia, with each stone carrying its own unique narrative and cultural significance. Turquoise stands as the oldest of the group, with a legacy that stretches back thousands of years. It is one of the oldest known birthstones, revered across ancient civilizations for its protective qualities and distinctive color. Its name is derived from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe from Turkey via the Silk Road. However, its use predates this by centuries; ancient Egyptians, Persians, and Native American tribes all prized turquoise for ceremonial and decorative purposes. Its status as a traditional December birthstone is deeply rooted in this ancient heritage.
Zircon, another of the traditional stones, has a long and sometimes misunderstood history. Often mistaken for diamond due to its exceptional brilliance and fire, zircon has been used in jewelry since the Middle Ages. The confusion with synthetic cubic zirconia has further obscured its reputation, but natural zircon is a distinct and valuable gem. Its history is tied to its fiery sparkle, which has made it a popular gem for centuries, particularly in its colorless and blue varieties. As a December birthstone, zircon represents a link to this historical appreciation for gemstone brilliance.
Tanzanite is the most recent addition to the December family, a true gem of the modern era. Discovered in the 20th century in a single, small area of Tanzania, its journey to birthstone status was remarkably swift. The gemological community and jewelers quickly recognized its unique beauty and pleochroic properties. By the late 20th century, its popularity had surged, leading to its official recognition as a December birthstone. Its story is one of modern discovery and rapid adoption into the gemstone lexicon.
Blue Topaz, while a topaz variety that has been known for centuries, gained its prominence as a December birthstone more recently. Historically, topaz was often associated with yellow or golden hues, but the development of reliable treatment processes to produce stable, vivid blue colors made blue topaz widely available and affordable. This availability, coupled with its attractive color and durability, led to its inclusion as a modern December birthstone. Its rise reflects the influence of the contemporary jewelry market and consumer preferences for bright, accessible gemstones.
Geological Formation and Sources
The geological origins of these four stones are as diverse as their appearances, with each forming under different conditions and originating from distinct parts of the world.
Turquoise is a hydrous phosphate of copper and aluminum, forming in arid regions where acidic, copper-rich groundwater interacts with aluminum-bearing rocks. This process occurs over millions of years, creating nodules and veins. The most significant sources are in the United States (particularly Arizona, New Mexico, and Nevada), Iran, China, and Egypt. The stone’s color, ranging from sky blue to greenish-blue, is directly influenced by the presence of copper (blue) and iron or chromium (green). The matrix, or the host rock embedded in the turquoise, is a key characteristic of many specimens, especially from American mines.
Zircon is a zirconium silicate that crystallizes from magma as it cools, often found in igneous and metamorphic rocks. It is a durable mineral that can survive geological processes, making it one of the oldest minerals on Earth. Major sources include Australia (which produces a significant portion of the world’s zircon, often as a byproduct of mining), Cambodia, Sri Lanka, Thailand, and Myanmar. The blue variety of zircon, which is particularly prized for December, is typically achieved through heat treatment of brownish zircon crystals.
Tanzanite is a variety of the mineral zoisite, colored by trace amounts of vanadium. It is found exclusively in the Merelani Hills of Northern Tanzania, near Mount Kilimanjaro. This single-source origin makes tanzanite exceptionally rare. The gem forms under specific geological conditions involving the metamorphism of host rocks. Due to its limited geographic occurrence, the supply of tanzanite is finite, adding to its value and allure.
Blue Topaz is a variety of the mineral topaz, which is a fluoro-aluminum silicate. Natural blue topaz is relatively rare; the vivid blue stones seen in the market are almost always the result of irradiation and heat treatment of colorless or pale blue topaz crystals. The primary sources for the rough material include Brazil, Sri Lanka, Nigeria, and Mexico. The treatment process is a standard industry practice and is generally disclosed to consumers, making blue topaz an affordable and consistently colored blue gemstone.
Gemological Properties
Understanding the physical and optical properties of these gemstones is crucial for appreciating their unique characteristics and for making informed decisions about care and wear.
| Gemstone | Chemical Composition | Hardness (Mohs) | Refractive Index | Key Properties |
|---|---|---|---|---|
| Turquoise | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | 1.61 - 1.65 | Porous, often contains a matrix; color varies with copper/iron content. |
| Zircon | ZrSiO₄ | 6.5 - 7.5 | 1.92 - 2.01 | High refractive index and strong dispersion ("fire"); pleochroic. |
| Tanzanite | Ca₂Al₃(SiO₄)₃(OH) | 6.5 - 7 | 1.69 - 1.70 | Strong trichroism (blue, violet, burgundy); heat-sensitive. |
| Blue Topaz | Al₂SiO₄(F,OH)₂ | 8 | 1.61 - 1.63 | Very hard; color is almost always from irradiation/heat treatment. |
Turquoise is relatively soft and porous, with a hardness of 5 to 6 on the Mohs scale. This makes it susceptible to scratches and chemicals. Its porosity means it can absorb oils and liquids, which can affect its color and stability. High-quality turquoise is valued for its even color and minimal matrix, though some styles celebrate the natural webbing.
Zircon is significantly harder and more durable, with a hardness of 6.5 to 7.5. Its most remarkable optical property is its high refractive index and strong dispersion, which gives it a fiery sparkle that can rival diamond. Blue zircon is typically heat-treated to achieve its color, but it is a naturally occurring variety. It is also pleochroic, showing different shades of blue from different crystal directions.
Tanzanite has a hardness of 6.5 to 7, making it moderately durable but more fragile than topaz or diamond. Its defining characteristic is its strong trichroism—displaying three distinct colors (typically blue, violet, and burgundy-red) depending on the crystal orientation. This pleochroic nature requires skilled cutting to maximize the desired blue-violet hue. It is also heat-sensitive and can be damaged by sudden temperature changes.
Blue Topaz is one of the hardest and most durable of the four, with a hardness of 8 on the Mohs scale. This makes it an excellent choice for jewelry that will be worn daily, such as engagement rings. Its color is consistent and vivid, a result of modern treatment processes. It has good clarity and is typically faceted to enhance its brilliance.
Symbolism and Metaphysical Beliefs
Each of December’s birthstones carries a legacy of symbolic meaning and metaphysical belief, often rooted in ancient traditions and modern interpretations.
Turquoise is widely regarded as a stone of protection, grounding, and good fortune. Across many cultures, it has been worn as an amulet to ward off negative energy and bring calm. Its stabilizing influence is often sought during times of change or stress, making it a symbol of emotional balance and well-being.
Tanzanite is associated with transformation, intuition, and new beginnings. Its striking blue-violet color is seen as a reflection of spiritual awakening and the clarity that comes with personal growth. It is often linked to the throat and third eye chakras, believed to enhance communication and psychic abilities.
Zircon is traditionally linked to wisdom, clarity, and balance. It is thought to sharpen the mind and boost mental focus, helping to clear confusion and promote self-confidence. Its fiery brilliance is seen as a metaphor for inner light and spiritual clarity.
Blue Topaz, with its serene sky-blue color, is associated with calm, communication, and truth. It is believed to soothe the emotions and encourage honest self-expression. As a modern gem, its symbolism often revolves around clarity of thought and peacefulness, aligning with its tranquil appearance.
Care and Cleaning
Proper care is essential to preserve the beauty and longevity of these gemstones, and their requirements vary significantly based on their physical properties.
Turquoise requires the most careful handling due to its softness and porosity. It should be cleaned with only a soft, damp cloth and mild soap, avoiding any harsh chemicals, ultrasonic cleaners, or steam. It is best to remove turquoise jewelry before activities that could cause impact or expose it to cosmetics, perfumes, or lotions. To maintain its color, it should be stored away from direct sunlight and heat.
Zircon is relatively durable but can be brittle due to its crystal structure. It is best cleaned with warm, soapy water and a soft brush, avoiding sudden temperature changes. While it is hard, it can be chipped by a sharp blow, so it is advisable to store it separately from other jewelry to prevent scratching.
Tanzanite is sensitive to heat and rapid temperature changes, which can cause internal fractures. It should never be cleaned in an ultrasonic cleaner or exposed to steam. Cleaning with a soft brush, mild detergent, and lukewarm water is safe. Due to its moderate hardness and cleavage, it should be handled with care to avoid impacts.
Blue Topaz, being very hard and durable, is the easiest to care for among the four. It can be cleaned safely in an ultrasonic cleaner (except when set with fragile stones) and with warm, soapy water. It is resistant to most chemicals, making it suitable for everyday wear. However, as with all gems, it is wise to avoid extreme impacts and store it properly to prevent scratches from harder materials.
Conclusion
The four birthstones of December—Turquoise, Tanzanite, Blue Topaz, and Zircon—offer an unparalleled diversity of beauty, history, and meaning. From the ancient, protective talisman of turquoise to the modern, transformative allure of tanzanite; from the fiery brilliance of zircon to the accessible, serene blue of topaz, each gemstone provides a unique connection to the month’s spirit. This multiplicity is not merely a commercial expansion but a celebration of the varied ways in which gemstones can resonate with individual personalities and preferences. Whether chosen for their historical significance, geological rarity, symbolic power, or simply their stunning color, these four gems ensure that every December-born individual has a radiant stone to call their own, embodying the cool elegance and reflective quiet of the year’s final month.