The month of December is uniquely associated with a spectrum of blue gemstones, each offering distinct beauty, history, and properties. While traditional lists have historically centered on turquoise and zircon, modern additions like tanzanite and blue topaz have expanded the options for those born in the twelfth month. This article explores the gemological characteristics, historical lore, and practical care of these four celebrated December birthstones: tanzanite, turquoise, zircon, and blue topaz. Drawing from authoritative gemological sources, we will examine what makes each stone a worthy emblem for December birthdays.
Historical Context and the Evolution of December's Birthstones
The tradition of assigning specific gemstones to each month has ancient roots, with practices documented in the biblical breastplate of the High Priest and later formalized in various cultural systems. For December, the historical record shows a progression from a few traditional stones to a more diverse modern selection.
Turquoise and Zircon: The Traditional Pillars Turquoise is one of the oldest known gemstones, with evidence of its use dating back to ancient Egypt, where pharaohs and royalty adorned themselves with it. It was believed to possess protective powers, guaranteeing health and good fortune. In ancient China, artisans carved turquoise more than 3,000 years ago. By the 13th century, European beliefs held that the stone could protect the wearer from falling, particularly from horses, and would break to warn of impending disaster. Hindu mystics associated it with wealth, believing that seeing turquoise after the new moon ensured fantastic riches. Similarly, Native American cultures, such as the Apache, revered the stone, with legends suggesting it could be found by following a rainbow to its end.
Zircon, the other traditional December stone, has a history that also stretches back millennia. The name "zircon" may derive from the Persian word "zargun," meaning gold-colored, though it is now celebrated for its brilliant blue variety. While specific historical narratives for zircon are less detailed in the provided sources, its enduring status as a December birthstone is well-established in modern gemological lists.
Modern Additions: Tanzanite and Blue Topaz The modern list of December birthstones has expanded to include tanzanite and blue topaz. Tanzanite, a relatively recent discovery, was added to the birthstone list in 2002, offering a vibrant violet-blue alternative. Blue topaz, while topaz itself has a long history, gained prominence as a modern December birthstone, particularly in the United States, due to its appealing blue hues and relative affordability.
The Gemological Institute of America (GIA) and other authoritative bodies now recognize a quartet of stones for December: turquoise, tanzanite, zircon, and blue topaz. This expansion provides individuals born in December with a wider array of choices in terms of color, durability, and price, allowing for greater personalization in jewelry selection.
Geological Formation and Primary Sources
Understanding where these gemstones originate provides insight into their rarity and value. Each stone forms under different geological conditions and is sourced from distinct regions around the world.
Turquoise Turquoise is an opaque mineral that forms in arid regions where acidic, copper-rich water percolates through aluminum- and phosphorus-bearing rocks. The presence of copper imparts its characteristic blue color, while iron can shift the hue toward green. Major sources include the United States (notably Arizona and New Mexico), Iran, China, and Tibet. The stone often contains a "matrix," which is the remnants of the host rock, adding unique patterning to each specimen.
Tanzanite Tanzanite is a variety of the mineral zoisite and is found exclusively in a single, small mining area near Mount Kilimanjaro in Tanzania, East Africa. Its formation is linked to the geological processes that created the East African Rift Valley. This limited geographic source contributes significantly to its rarity and value. The stone's vivid blue-to-violet color is the result of heat treatment, which is applied to most tanzanite after mining to stabilize its color and enhance its vibrancy.
Zircon Zircon is a mineral that forms in igneous and metamorphic rocks. It is one of the oldest minerals on Earth, with crystals found in ancient crustal rocks. While zircon occurs in many colors, the blue variety used for December birthstones is typically heat-treated to achieve its desirable hue. Major sources include Australia, Cambodia, Sri Lanka, and the United States. Australia is a particularly significant producer of zircon, though the gemstone is mined in various other locations globally.
Blue Topaz Blue topaz is a variety of the topaz mineral, which crystallizes in igneous rocks, particularly in pegmatites and high-temperature veins. Natural blue topaz is exceedingly rare; virtually all blue topaz on the market is created by irradiating and heat-treating colorless or pale yellow topaz. The United States is a notable source for topaz, with the state of Texas having designated blue topaz as its official state gemstone. Other sources include Brazil, Nigeria, and Sri Lanka. The stone can be found in states like Texas, Utah, and California, though commercial mining is limited.
Gemological Properties
The distinct physical and optical properties of each December birthstone determine its durability, suitability for jewelry, and aesthetic appeal. The following table summarizes key gemological data for each stone, based on information from authoritative sources.
| Gemstone | Color Range | Hardness (Mohs Scale) | Luster | Transparency | Refractive Index (Approx.) | Specific Gravity | Key Characteristics |
|---|---|---|---|---|---|---|---|
| Turquoise | Blue to green | 5 to 6 | Waxy to dull | Opaque to slightly translucent | 1.61 - 1.65 | 2.6 - 2.8 | No cleavage; brittle; often stabilized. |
| Zircon | Blue, yellow, red, brown | 6 to 7.5 | Vitreous (glassy) | Transparent to translucent | 1.92 - 2.01 | 3.9 - 4.7 | High refractive index; poor cleavage. |
| Tanzanite | Blue to violet-blue | 6 to 7 | Vitreous | Transparent to translucent | 1.69 - 1.70 | 3.35 | Pleochroic; heat-treated for color. |
| Blue Topaz | Sky-blue to deep London blue | 8 | Vitreous | Transparent | 1.63 - 1.64 | 3.53 | Typically irradiation-treated; very hard. |
Turquoise With a hardness of 5 to 6 on the Mohs scale, turquoise is relatively soft and can be prone to scratches and breakage. Its waxy to dull luster and opaque nature make it ideal for cabochon cuts, often used in pendants, earrings, and statement rings. The stone lacks cleavage but can be brittle. Due to its porosity, turquoise is frequently stabilized with resins or dyed to improve its durability and color uniformity.
Zircon Zircon is significantly harder than turquoise, ranging from 6 to 7.5 on the Mohs scale, making it more suitable for various jewelry types, including rings. Its vitreous luster and high refractive index (1.92 to 2.01) give it exceptional brilliance and fire, often compared to that of diamond. While it has poor cleavage, it can be sensitive to sudden temperature changes. Blue zircon, the most popular variety for December, is prized for its vibrant sparkle.
Tanzanite Tanzanite has a hardness of 6 to 7 on the Mohs scale, placing it in the moderate range for jewelry durability. It exhibits a vitreous luster and is typically transparent to translucent. One of its most notable properties is pleochroism, meaning it displays different colors (blue, violet, and burgundy) when viewed from different angles. This characteristic requires careful cutting to showcase the desired blue hue. Most tanzanite is heat-treated to achieve its stable, vivid blue color, a standard practice in the gem trade.
Blue Topaz Blue topaz is the hardest of the December birthstones, with a Mohs hardness of 8, making it extremely durable and resistant to scratching. It has a vitreous luster and is transparent, allowing for brilliant faceted cuts that enhance its color and sparkle. As mentioned, the blue color is almost exclusively the result of post-mining treatments, which are stable and permanent. Its combination of hardness, clarity, and attractive blue color makes it a popular choice for a wide range of jewelry designs.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these gemstones have been imbued with symbolic meanings and metaphysical properties, adding a layer of significance beyond their physical beauty.
Turquoise Turquoise has been associated with protection, healing, and good fortune. Ancient Egyptians believed it offered spiritual guidance and safeguarded the wearer. In many cultures, it was considered a talisman against evil and accidents. The Apache believed it could guide one to treasure, and Hindu traditions linked it to wealth and the moon. Its color, reminiscent of the sky and water, has universally symbolized tranquility and peace.
Zircon Historically, zircon was believed to promote honor, purity, and wisdom. It was thought to aid in sleep and bring prosperity. The blue variety, in particular, has been associated with clarity of thought and spiritual protection. Its brilliant sparkle was often likened to the stars, connecting it to celestial guidance.
Tanzanite As a modern addition, tanzanite's symbolism is more contemporary. It is often associated with transformation, spiritual awakening, and higher consciousness. Its unique violet-blue color is said to stimulate the throat and third eye chakras, enhancing communication and intuition. It is frequently gifted as a symbol of new beginnings and profound change.
Blue Topaz Blue topaz is linked to calmness, love, and fidelity. Its soothing blue hue is believed to promote tranquility and reduce stress. In modern times, it is often associated with emotional balance and clear communication, making it a popular gift for romantic occasions and a symbol of enduring affection.
Care and Cleaning Recommendations
Proper maintenance is essential to preserve the beauty and longevity of these gemstones. Their varying hardness and chemical compositions dictate specific care guidelines.
Turquoise Due to its softness (5-6 Mohs) and porosity, turquoise requires gentle care. It should be cleaned with a soft, damp cloth and mild soap; avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. Store it separately to prevent scratches from harder stones. Avoid prolonged exposure to sunlight, cosmetics, and perfumes, which can cause discoloration over time.
Zircon Zircon's hardness (6-7.5 Mohs) makes it relatively durable, but it can be brittle due to poor cleavage. It is safe to clean with warm soapy water and a soft brush. Avoid sudden temperature changes and impacts, which can cause fracture. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided.
Tanzanite With a hardness of 6-7, tanzanite should be handled with care. Clean it using warm soapy water and a soft brush. Avoid ultrasonic cleaners and steam, as the heat and vibrations can damage the stone. Due to its popularity and value, it is advisable to store tanzanite jewelry in a padded box to prevent scratches.
Blue Topaz Blue topaz's high hardness (8 Mohs) makes it very easy to care for. It can be cleaned with warm soapy water, a soft brush, and even an ultrasonic cleaner. However, it is best to avoid steam cleaning, as extreme heat can potentially damage the stone or any treatments it has undergone. Its durability makes it suitable for everyday wear in rings and bracelets.
Conclusion
The December birthstones—tanzanite, turquoise, zircon, and blue topaz—offer a remarkable diversity of color, history, and meaning. From the ancient, protective turquoise to the fiery brilliance of zircon, the transformative violet of tanzanite, and the serene blue of topaz, each gemstone provides a unique connection to the natural world and human culture. Their varied gemological properties allow for a wide range of jewelry applications, from delicate pendants to durable rings. Whether chosen for their symbolic significance, aesthetic appeal, or historical depth, these azure-hued stones provide a meaningful and beautiful way to celebrate a December birthday, embodying the cool elegance and profound beauty of the winter month.