Individuals born in the final month of the year are uniquely fortunate, being associated with three distinct and visually captivating gemstones: tanzanite, turquoise, and zircon. Unlike most months that claim a single birthstone, December is represented by a "blue trio," each stone sharing a predominantly cool color palette that evokes the crispness of winter while offering its own unique geological story, historical significance, and aesthetic appeal. These gemstones—tanzanite, turquoise, and zircon—are celebrated for their diverse shades of blue, ranging from the sky-blue of turquoise to the deep violet-blue of tanzanite and the brilliant, colorless to blue hues of zircon. This guide provides a comprehensive exploration of these three remarkable gems, detailing their origins, gemological properties, historical lore, and practical care, drawing exclusively from established gemological sources.
History and Lore of the Blue Trio
The historical narratives of December's birthstones are as varied as their colors, spanning millennia and continents. Each gem carries a rich heritage of cultural belief and symbolic meaning.
Turquoise: The Ancient Talisman Turquoise is arguably the oldest of the three birthstones in terms of human use and reverence. Its history stretches back thousands of years, with evidence of its use found in ancient Egyptian tombs. Pharaohs were entombed with turquoise artifacts, as the stone symbolized eternal life and was believed to ward off evil spirits. In ancient Egyptian culture, it was a sacred stone, associated with power and immortality. Beyond Egypt, turquoise held a significant place in Native American culture, where it served as a ceremonial gem and a medium of exchange. Across various cultures, the stone has been consistently associated with the hues of the sky and water, symbolizing life, joy, and abundance.
Tanzanite: The Modern Marvel In stark contrast to turquoise's ancient lineage, tanzanite is a very recent addition to the gemstone world. This captivating violet-blue gem was discovered in 1967 in the Merelani Hills of Northern Tanzania, near the iconic Mount Kilimanjaro. Its name is derived directly from its country of origin. Tanzanite is a variety of the mineral zoisite and is prized for its remarkable trichroism, a gemological property that allows it to appear in three different colors—blue, purple, and burgundy—depending on the viewing angle. Its rarity is underscored by the fact that it is found in only one small geographic location on Earth, making it one of the world's rarest gemstones.
Zircon: The Earth's Oldest Mineral Zircon boasts a history that is not measured in human millennia but in geological eons. With a history spanning over 4.4 billion years, it is one of the oldest minerals found on Earth. This ancient stone has a stunning brilliance, particularly in its colorless and blue varieties, which often leads to a common misconception: confusion with cubic zirconia, a synthetic diamond simulant. It is crucial to distinguish natural zircon from this laboratory-created material. Blue zircon, a popular December birthstone, is sourced from various locations across the globe.
Geological Formation and Sources
Understanding the geological origins and primary mining locations of these gems provides insight into their rarity and unique characteristics.
Turquoise Formation and Sources Turquoise is a mineral that forms in arid regions where acidic, copper-rich groundwater interacts with aluminum-bearing minerals. This process occurs over millions of years, depositing turquoise in veins and nodules within host rock. The gem's distinctive color comes from its copper content, while traces of iron can create a greenish tint. Major sources for turquoise are concentrated in specific global regions known for their dry climates. Historically and in the present day, the most renowned sources include: * Iran (formerly Persia): Known for producing "Persian turquoise," often considered the benchmark for quality, characterized by its pure "robin's egg blue" color. * The Southwestern United States: A region with a long history of turquoise mining, including states like Arizona and New Mexico, which produce stones in a wide range of colors and matrix patterns. * Mexico: Another significant source, known for its distinct shades of blue and green turquoise.
Tanzanite Formation and Sources Tanzanite's formation is a unique geological event. It is a variety of zoisite that was subjected to intense heat and pressure, a process that is believed to have occurred during the formation of the East African Rift Valley. This metamorphism transformed the brownish zoisite crystals into the vibrant blue-violet material we know as tanzanite. The geological conditions required for this transformation were incredibly specific, which is why tanzanite's occurrence is limited to a tiny area of approximately four square kilometers at the base of Mount Kilimanjaro in Tanzania. This extreme geographic limitation is the primary factor contributing to its rarity.
Zircon Formation and Sources Zircon is a nesosilicate mineral that is highly resistant to weathering and heat, making it one of the most durable minerals on Earth. It crystallizes from magma as a primary mineral in igneous rocks and is also found in metamorphic rocks. Because it is so durable, it is also commonly found in sedimentary deposits as detrital grains. Its presence in very old rocks makes it a key mineral for radiometric dating of the Earth's crust. Colorless zircon and blue zircon are found in numerous locations worldwide, including: * Cambodia * Sri Lanka * Thailand * Australia * The United States
Gemological Properties
The physical and optical properties of a gemstone determine its durability, appearance, and value. The December birthstones have distinct profiles.
| Gemstone | Mineral Family | Chemical Composition | Hardness (Mohs Scale) | Key Optical Property |
|---|---|---|---|---|
| Turquoise | Phosphate | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | Opaque, waxy luster |
| Tanzanite | Zoisite (Sorosilicate) | Ca₂Al₃(SiO₄)₃(OH) | 6.5 - 7 | Trichroism (blue, purple, burgundy) |
| Zircon | Zirconosilicate | ZrSiO₄ | 7.5 | High refractive index, brilliance |
Turquoise Properties * Color: Its color ranges from sky blue to greenish-blue. The most prized color is a "robin's egg blue." * Hardness: Turquoise has a Mohs hardness of 5 to 6, making it a relatively soft gemstone. It is also porous and can be susceptible to discoloration from chemicals, oils, and even the skin's natural acidity. * Clarity and Structure: Turquoise is typically an opaque gemstone. It often contains a "matrix," which is the host rock (often brown or black) that remains embedded within the turquoise mineral.
Tanzanite Properties * Color: The gem is celebrated for its intense violet-blue hue. The color is often enhanced by a controlled heat treatment, which removes brownish undertones and brings out the desirable blue and violet colors. * Hardness: With a Mohs hardness of 6.5 to 7, tanzanite is suitable for jewelry but requires some care to avoid scratches and impacts. * Clarity: Tanzanite is typically a transparent stone. High-quality tanzanite is "eye-clean," meaning it has no visible inclusions. * Trichroism: This is its most famous property. When viewed from different crystallographic directions, the stone can display three distinct colors: blue, violet, and a reddish-burgundy.
Zircon Properties * Color: Zircon occurs in a wide spectrum of colors, including colorless, yellow-gold, and the popular blue. The blue color in zircon is often achieved through a heat treatment process. * Hardness: Zircon is a durable gemstone with a Mohs hardness of 7.5, making it resistant to scratching and suitable for a variety of jewelry types, including rings. * Brilliance: Zircon possesses a high refractive index, which gives it exceptional brilliance and fire, often compared to that of a diamond. This brilliance is what historically made colorless zircon a popular diamond simulant before the advent of cubic zirconia.
Symbolism and Metaphysical Beliefs
Across cultures and through history, gemstones have been imbued with symbolic meanings and metaphysical properties. The December birthstones are particularly rich in such lore.
Turquoise: The Stone of Protection and Healing Turquoise has long been regarded as a sacred stone and a powerful talisman. It is widely believed to offer protection from negative energy and harm. Its connection to the sky and water has made it a symbol of life, joy, and abundance. In modern metaphysical beliefs, turquoise is said to support the immune system and aid in detoxification, promoting overall physical and spiritual well-being.
Tanzanite: The Stone of Compassion and Calm As a relatively new gemstone, tanzanite's metaphysical lore is modern but potent. It is associated with higher consciousness and spiritual awakening. Practitioners believe that tanzanite can foster compassion and calmness, helping to soothe turbulent emotions. Some sources also attribute physical healing properties to it, suggesting it can improve skin and hair health.
Zircon: The Stone of Wisdom and Sleep Zircon is one of the traditional birthstones for Sagittarius and is believed to bring wisdom and clarity to its wearer. It is also associated with prosperity and is thought to attract wealth. In the realm of physical and spiritual wellness, zircon is believed to promote restful sleep and ward off nightmares, making it a stone of peace and tranquility.
Care and Cleaning for December Birthstones
Due to their varying levels of hardness and stability, the December birthstones require different care routines to maintain their beauty and integrity.
Caring for Turquoise Because of its relative softness and porosity, turquoise requires the most care. * Avoid Chemicals: Keep turquoise away from perfumes, lotions, hairsprays, and household cleaners. These substances can damage the stone's surface and alter its color. * Gentle Cleaning: Clean turquoise with warm water, a mild soap, and a soft cloth. Avoid ultrasonic cleaners and steam cleaners. * Storage: Store turquoise separately from other jewelry to prevent scratching. A soft pouch is ideal.
Caring for Tanzanite Tanzanite is durable enough for everyday wear but should be handled with care. * Avoid Impacts: While hard enough to resist scratches, tanzanite can be brittle and may chip or fracture if subjected to a hard blow. * Cleaning: The best method for cleaning tanzanite is with warm, soapy water and a soft brush. As with turquoise, avoid ultrasonic and steam cleaners, as the heat and vibrations can damage the stone. * Storage: Store tanzanite jewelry in a soft cloth or padded jewelry box to protect it from being scratched by harder gems.
Caring for Zircon Zircon is a relatively hard and durable gemstone, but it can be brittle. * Avoid Sharp Blows: Due to its brittleness, zircon can be damaged by sharp impacts. It is advisable to remove zircon jewelry during strenuous activities. * Cleaning: Zircon can be cleaned safely with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided due to the potential for fracturing if the stone has inclusions. * Storage: Store zircon pieces carefully to prevent them from scratching other gems or being scratched themselves.
Conclusion
The December birthstones—tanzanite, turquoise, and zircon—offer a remarkable trio of choices for those born in the last month of the year. Each gem presents a unique narrative: turquoise, the ancient talisman revered for its protective qualities and sky-blue hue; tanzanite, the modern marvel from Tanzania, prized for its rare violet-blue color and trichroic magic; and zircon, the ancient mineral with a history as old as the Earth itself, celebrated for its brilliant fire and durability. Together, they form a collection that spans the full spectrum of blue, embodying wisdom, protection, and spiritual growth. Whether chosen for its historical depth, geological rarity, or aesthetic beauty, any of these three stones provides a meaningful and enduring connection to the natural world and the tradition of birthstones.