December is a unique month in the world of birthstones, boasting not one, but four official gems: Tanzanite, Zircon, Turquoise, and Blue Topaz. Each of these stones presents a captivating shade of blue, mirroring the cool tones of the winter season, and carries with it a rich history and distinct symbolism. While Turquoise holds the distinction as the most traditional December birthstone, admired for centuries, Tanzanite is the newest addition, discovered in Tanzania in 1967. These gemstones are associated with qualities like wisdom, protection, and new beginnings, offering a diverse range of options for those born in December to express their individuality.
A Quartet of Color: Historical and Cultural Significance
The association of specific gemstones with particular months has evolved over time. Historically, the selection of birthstones was often linked to astrological signs, with different gems believed to hold power related to the zodiac. While the modern list of birthstones is largely standardized, December’s selection reflects a blend of ancient tradition and more recent discoveries.
Turquoise, with its long and illustrious history, has been prized for millennia. Ancient cultures cherished it for its spiritual and healing qualities. Zircon, also possessing a long history, is believed to bestow wisdom, prestige, and wealth upon its wearer. Blue Topaz symbolizes friendship, romance, eternal loyalty, as well as good fortune and success. Tanzanite, the most recent addition to the December birthstone family, quickly gained popularity for its striking violet-blue shimmer, often compared to that of sapphire, and its elegant, luxurious appearance.
Geological Origins and Mining Locations
The geological origins of these four December birthstones are remarkably diverse. Turquoise, a hydrated phosphate of copper and aluminum, forms in relatively dry, arid environments, often in association with copper deposits. Its presence is often found in the vicinity of sapphire sources, including locations in Sri Lanka, Australia, Myanmar, Vietnam, and Cambodia.
Zircon, a zirconium silicate, is found in a variety of geological settings, including igneous, metamorphic, and sedimentary rocks. It occurs in many colors, but the blue variety is particularly favored as a December birthstone.
Tanzanite, a unique form of the mineral zoisite, is exceptionally rare, found only in the Merelani Hills near the foot of Mount Kilimanjaro in northern Tanzania. Its distinctive blue and violet hues are attributed to the presence of vanadium within the zoisite crystals. The gemstone formed approximately 585 million years ago during intense plate tectonic activity and extreme heat.
Blue Topaz, a variety of the aluminum silicate mineral topaz, is found in various locations worldwide, though specific mining details are not provided in the available sources.
Gemological Properties: A Comparative Overview
Each of the December birthstones possesses unique gemological properties that contribute to its beauty and desirability.
Turquoise: A hydrated copper aluminum phosphate, its color ranges from sky blue to greenish-blue. Zircon: A zirconium silicate, with a hardness ranging from 6 to 7.5 on the Mohs scale. It exhibits a variety of colors, including blue, golden, red, and clear. Tanzanite: A calcium aluminum hydroxyl sorosilicate, with a hardness of 6 to 7 on the Mohs scale. It displays pleochroism, meaning it exhibits different colors when viewed from different angles. Blue Topaz: An aluminum silicate fluoride hydroxide, with a hardness of 8 on the Mohs scale.
The following table summarizes key gemological properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Color(s) | Notable Properties |
|---|---|---|---|---|
| Turquoise | Hydrated Copper Aluminum Phosphate | 5-6 | Sky Blue to Greenish-Blue | Opaque, often with matrix inclusions |
| Zircon | Zirconium Silicate | 6-7.5 | Blue, Golden, Red, Clear | High dispersion, can resemble diamond |
| Tanzanite | Calcium Aluminum Hydroxyl Sorosilicate | 6-7 | Blue, Violet | Pleochroism, color changes with lighting |
| Blue Topaz | Aluminum Silicate Fluoride Hydroxide | 8 | Blue | Excellent brilliance, durable |
Color Variations and Treatments
The color of each gemstone can vary significantly, and treatments are often employed to enhance their appearance. Zircon is commonly heat-treated to produce blue and colorless varieties, as well as orange, yellow, and red hues. Prolonged exposure to bright light can sometimes cause heat-treated zircon to revert to its original color, typically a light brown. Exposure to heat can also alter the color of some zircon.
Tanzanite, in its natural form, often appears brownish or yellowish-green, with flashes of blue and violet. Heat treatment is routinely used to remove the brownish color and reveal the more intensely blue and violet hues that characterize this gemstone. The resulting color change is permanent, and does not introduce any additional durability concerns. The way a cutter crafts the gem can also influence its overall color.
Care and Cleaning Recommendations
Proper care is essential to maintain the beauty of these December birthstones. Zircon, with a hardness of 6 to 7.5, is susceptible to abrasion and should be protected from rough wear. Avoid wearing it during activities like gardening, sports, or dishwashing. Cleaning should be done with a soft brush and mild soap in warm water; ultrasonic and steam cleaners are not recommended.
Tanzanite, also with a hardness of 6 to 7, is resistant to the effects of normal heat, light, and common chemicals. However, it can crack if exposed to very high temperatures or sudden temperature changes. It is also prone to abrasion. Warm, soapy water is the best method for cleaning tanzanite; ultrasonic and steam cleaners should be avoided. Setting tanzanite in earrings or pendants is recommended, as it is not ideal for daily wear in a ring.
Specific care instructions for Turquoise and Blue Topaz are not detailed in the provided sources.
Symbolism and Metaphysical Beliefs
Beyond their aesthetic appeal, these December birthstones are imbued with symbolic meaning. Zircon is believed to bring wisdom, prestige, and wealth to its wearer. Tanzanite is thought to stimulate creativity. Blue Topaz signifies friendship, romance, eternal loyalty, as well as good fortune and success. While the sources do not elaborate on the metaphysical properties of Turquoise, it has long been revered for its spiritual and healing qualities in many cultures.
Conclusion
The December birthstones – Tanzanite, Zircon, Turquoise, and Blue Topaz – represent a captivating spectrum of color, history, and symbolism. From the ancient origins of Turquoise to the recent discovery of Tanzanite, each gem offers a unique connection to the winter season and a meaningful way for December-born individuals to express their personal style and beliefs. The diversity of these stones ensures that there is a perfect December birthstone to suit every taste and preference.