December 13th is a unique date in the calendar of birthstones, distinguished by not one, but three associated gemstones: Tanzanite, Turquoise, and Zircon. Each of these gems carries its own rich history, captivating color, and symbolic meaning, making them particularly special for those born on this day. This article will explore the origins, geological context, and cultural significance of these three December birthstones, offering a comprehensive overview of their properties and lore.
History and Lore
The tradition of associating specific gemstones with months of the year dates back centuries, with roots in ancient astrology and beliefs about the healing powers of stones. While many months have a single, established birthstone, December boasts a selection, reflecting the evolving understanding and appreciation of gemstones over time. Turquoise stands as one of the oldest known birthstones, adorning artifacts from ancient civilizations like the Egyptians and Chinese. Zircon, with a history stretching back millennia, has often been mistaken for diamond due to its brilliance. Tanzanite, however, is the youngest of the three, its discovery occurring as recently as 1967 in Tanzania.
Tanzanite’s relatively recent emergence hasn’t diminished its appeal. Named after its country of origin, Tanzania, the gem quickly gained popularity for its striking blue-violet hue and rarity. Though lacking the extensive historical record of older stones, Tanzanite has rapidly become associated with qualities like healing, protection, and personal transformation. Some believe it can activate key chakras, fostering spiritual connection and psychic abilities. Turquoise, conversely, has a long and storied past, appearing in the funerary mask of King Tut and continuing to be a cherished stone in modern jewelry. Zircon’s history is also extensive, with the name potentially originating from the Sanskrit word “tapas,” meaning fire, reflecting its historical association with strength and protection.
Geological Formation and Sources
The origins of these three birthstones are geographically diverse and reflect distinct geological processes. Turquoise, as one of the oldest known gemstones, forms through a secondary enrichment process. It is created by the weathering of copper-rich rocks in arid regions, where rainwater percolates through the rock, dissolving copper and other minerals. These minerals then precipitate in fissures and cavities, forming the characteristic blue-green gemstone.
Zircon, a silicate mineral, forms in a variety of igneous rocks, including granite and pegmatite. It crystallizes under high-temperature conditions and is found in metamorphic rocks as well. Its diverse color palette, ranging from colorless to brown, red, and blue, is due to trace elements within its crystal structure. The blue varieties of zircon, particularly valued as December birthstones, are often created through heat treatment of colorless zircon.
Tanzanite’s origin is particularly unique. It is found exclusively in a small area near the Merelani Hills of northern Tanzania. This limited geographic source contributes significantly to its rarity and value. Tanzanite is a variety of the mineral zoisite, and its distinctive blue-violet color is attributed to the presence of trace amounts of vanadium. The geological conditions required for its formation are exceptionally specific, making it one of the rarest gemstones in the world.
Gemological Properties
Each of these December birthstones possesses unique gemological properties that contribute to its beauty and desirability.
Turquoise: This opaque gemstone typically ranges in color from sky blue to greenish-blue, often with matrix patterns (veins of the surrounding rock) visible within the stone. Its hardness on the Mohs scale is relatively low, ranging from 5 to 6, making it susceptible to scratching.
Zircon: Zircon exhibits a high refractive index, contributing to its brilliance and fire. It can be found in a wide range of colors, including colorless, brown, red, yellow, and blue. The blue varieties, often heat-treated, are particularly popular as December birthstones. Its hardness ranges from 6.5 to 7.5 on the Mohs scale, making it more durable than turquoise.
Tanzanite: This gemstone is known for its trichroism, meaning it displays three different colors – blue, violet, and burgundy – depending on the viewing angle. Its color is highly sensitive to lighting conditions, appearing more blue under daylight and more violet under incandescent light. Tanzanite has a hardness of 6 to 7 on the Mohs scale.
Here's a table summarizing the key gemological properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Color(s) | Notable Properties |
|---|---|---|---|---|
| Turquoise | CuAl6(PO4)4(OH)8·4H2O | 5-6 | Sky blue to greenish-blue | Opaque, matrix patterns |
| Zircon | ZrSiO4 | 6.5-7.5 | Colorless, brown, blue, red | High refractive index |
| Tanzanite | Ca2Al3(SiO4)3(OH) | 6-7 | Blue, violet, burgundy | Trichroism |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been imbued with symbolic meanings and metaphysical properties. Turquoise has long been considered a protective stone, believed to ward off negative energy and bring good fortune. It is also associated with friendship, loyalty, and communication. Zircon, historically linked to strength and protection, is now often associated with prosperity and wisdom.
Tanzanite, as a more recently discovered gem, has quickly gained associations with spiritual enlightenment and transformation. It is believed to open and balance the third eye chakra, fostering a deeper connection to intuition and psychic abilities. Some believe it encourages positive changes in life, promoting inner strength and resilience. The association of these stones with December may also stem from their colors, which evoke the cool, serene beauty of the winter season.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones. Turquoise, due to its relatively low hardness, is susceptible to scratching and should be protected from impact. It is best cleaned with a soft cloth and mild soapy water. Avoid harsh chemicals and ultrasonic cleaners. Zircon, being more durable, can be cleaned with warm soapy water and a soft brush. However, avoid sudden temperature changes, as this can cause fractures. Tanzanite requires gentle care. It is best cleaned with a soft cloth and mild soapy water. Avoid ultrasonic cleaners and harsh chemicals, as they can damage the stone. Due to its sensitivity to heat, avoid prolonged exposure to direct sunlight.
Conclusion
The December 13th birthstones – Tanzanite, Turquoise, and Zircon – represent a captivating blend of history, geological wonder, and symbolic meaning. From the ancient origins of Turquoise to the recent discovery of Tanzanite and the enduring brilliance of Zircon, each gem offers a unique connection to the beauty and mystery of the natural world. Whether chosen for their aesthetic appeal, their perceived metaphysical properties, or their historical significance, these radiant gems continue to captivate and inspire.