December, the final month of the year, is associated with a variety of stunning gemstones, each with its own unique history, symbolism, and gemological properties. The birthstones for December are turquoise, tanzanite, and blue zircon. These stones, ranging from deep blue to vibrant violet, have captivated jewelers, collectors, and historians for centuries. This article explores the rich heritage, geological makeup, and cultural significance of these December birthstones, drawing on a wealth of historical and scientific data.
History and Lore
Turquoise: The Ancient Gem of Protection
Turquoise is one of the oldest known gemstones, with a history stretching back thousands of years. Its use can be traced to burial sites in western Iran dating as far back as 7,000 BCE. In ancient Egypt, turquoise was highly valued and was often inlaid in jewelry, amulets, and even in the burial masks of pharaohs, including that of Tutankhamun. The Chinese have also long cherished turquoise, carving it into intricate works of art over 3,000 years ago.
Throughout history, turquoise was believed to possess powerful protective properties. It was used in horse bridles and worn by individuals to ward off falls. In some cultures, it was even believed that turquoise would break into pieces if disaster was imminent. In the 13th century, it was thought to protect the wearer from falling, especially off a horse. Hindu mystics believed that seeing a turquoise after observing a new moon would bring wealth and fortune.
Native American tribes also held turquoise in high esteem. It was used in ceremonies and was believed to promote positive energy, health, and spiritual well-being. The gemstone was often associated with the sky and was used in traditional jewelry to symbolize protection and harmony.
Tanzanite: The Modern Marvel
Tanzanite, in contrast, is a relatively recent discovery in the world of gemology. The first tanzanite crystal was found in 1967 by a Masai tribesman near Mount Kilimanjaro in Tanzania. This makes it the most recently discovered December birthstone. The gem is named after Tanzania, the only place in the world where it naturally occurs. The deposit is small, measuring just 4.3 miles long and 1.2 miles wide.
Tanzanite is a variety of the mineral zoisite and is known for its pleochroic properties, meaning it displays different colors depending on the viewing angle. It typically appears in shades of blue and violet and is often heat-treated to enhance its color. The discovery of tanzanite in the 20th century marked a significant addition to the world of gemstones and is a testament to the ongoing exploration and appreciation of Earth’s natural treasures.
Blue Zircon: The Oldest Mineral on Earth
Blue zircon is one of the oldest minerals on Earth, with some zircon crystals found in Australia estimated to be over 4 billion years old. Despite its ancient origins, blue zircon was only recognized as a December birthstone in the 20th century. The gemstone is often heat-treated to achieve its striking blue hue and is known for its brilliance and versatility in jewelry design.
Zircon is also found in a range of colors, including yellow, red, and colorless, but the blue variety is particularly popular. It is typically stable under light and chemical exposure, although some heat-treated zircons may revert to their original colors after prolonged exposure to bright light. This property makes it important for jewelers and collectors to understand proper care and handling techniques to preserve the gem’s beauty.
Geological Formation and Sources
Turquoise: A Product of Copper and Phosphate
Turquoise is formed through a geological process involving copper, aluminum, and phosphate. It is created when water containing copper and aluminum flows through phosphate-rich sediment. This process often results in the gemstone's characteristic blue color, although the presence of other elements like iron or zinc can cause variations in hue, producing greenish or yellowish tones.
The most valuable and sought-after turquoise comes from the American Southwest and Iran. The American Southwest, particularly areas in New Mexico and Arizona, is known for its high-quality turquoise deposits. In Iran, turquoise has been mined for centuries and is often found in vibrant blue tones. A rare variety known as "Golden Hills" is mined in Kazakhstan and is considered some of the purest turquoise in the world.
Tanzanite: A Unique Deposit in Tanzania
Tanzanite is unique in that it is found only in a small area in Tanzania, near Mount Kilimanjaro. This deposit is limited in size and is subject to geological constraints, making tanzanite a rare and valuable gemstone. The mineral is a variety of zoisite and is found in metamorphic rocks. Its pleochroic properties are a result of its internal structure, which causes different wavelengths of light to be absorbed and reflected in varying ways depending on the viewing angle.
The rarity of tanzanite's source has led to its high value in the gemstone market. The limited supply, combined with its vibrant colors and unique optical properties, makes tanzanite a prized possession for collectors and a popular choice for jewelry.
Blue Zircon: A Versatile and Durable Gemstone
Blue zircon is found in various parts of the world, including Sri Lanka, Australia, Myanmar, Vietnam, and Cambodia. These regions often overlap with areas where sapphires are found, which is one reason zircon is sometimes confused with sapphire. The gemstone is formed in a range of geological environments, including igneous and metamorphic rocks.
Zircon's hardness ranges from 6 to 7.5 on the Mohs scale, making it relatively durable for a gemstone. However, it is often heat-treated to enhance its color and stability. This treatment is crucial for achieving the deep blue hues that are so popular in jewelry. The gemstone's versatility in color and clarity, combined with its affordability, has made it a popular choice for both everyday and special occasion jewelry.
Gemological Properties
Turquoise
- Color: Ranges from blue to green, with veins or spider webs of matrix (remnants of the host rock).
- Hardness: 5 to 6 on the Mohs scale.
- Transparency: Semi-translucent to opaque.
- Luster: Waxy to glassy.
- Chemical Composition: A hydrated phosphate of copper and aluminum (CuAl₆(PO₄)₄(OH)₈·4H₂O).
- Formation: Formed by the action of water through phosphate-rich sediment, incorporating copper and aluminum.
Turquoise is often treated with waxes or resins to improve its durability and appearance. High heat can cause discoloration, and acids can damage the gemstone. For cleaning, warm, soapy water is recommended, while steam or ultrasonic cleaners should be avoided.
Tanzanite
- Color: Ranges from blue to violet and combinations of both.
- Hardness: 6 to 7 on the Mohs scale.
- Transparency: Transparent to translucent.
- Luster: Vitreous.
- Chemical Composition: A calcium aluminum silicate with traces of vanadium (Ca₂Al₃(SiO₄)₃(OH)) containing vanadium.
- Formation: Found in metamorphic rocks near Mount Kilimanjaro, Tanzania.
Tanzanite is pleochroic, displaying different colors depending on the angle of light. It is typically heat-treated to enhance its blue and violet hues. The gemstone is stable under light and chemical exposure but should be handled with care to avoid damage.
Blue Zircon
- Color: Ranges from blue to colorless, with heat treatment producing a wide range of colors.
- Hardness: 6 to 7.5 on the Mohs scale.
- Transparency: Transparent to translucent.
- Luster: Vitreous.
- Chemical Composition: Zirconium silicate (ZrSiO₄).
- Formation: Found in igneous and metamorphic rocks, often in areas where sapphires are also present.
Blue zircon is often heat-treated to achieve its vibrant blue color. Some stones may revert to their original colors after prolonged exposure to bright light. The gemstone is stable under chemical exposure but should be protected from abrasion in rough conditions.
Symbolism and Metaphysical Beliefs
Turquoise: A Stone of Protection and Positive Energy
Turquoise has long been associated with protection, positive energy, and spiritual well-being. In ancient Egypt, it was used in burial rituals and was believed to offer protection in the afterlife. Native American tribes used turquoise in ceremonies and believed it to be a powerful symbol of health, prosperity, and harmony.
In Hindu culture, turquoise was believed to bring wealth and fortune, especially when seen after a new moon. The gemstone was also thought to protect the wearer from falling, particularly when used in horse bridles. These beliefs have persisted through the centuries, and turquoise remains a popular choice for those seeking protection and positive energy.
Tanzanite: A Stone of Transformation and Intuition
Tanzanite is often associated with transformation, intuition, and emotional balance. As a relatively new gemstone, it has quickly gained a following among those who believe in its metaphysical properties. It is believed to enhance intuition and promote emotional healing. Its deep blue and violet hues are thought to resonate with the throat and third eye chakras, making it a popular stone for meditation and spiritual practices.
The rarity of tanzanite adds to its mystique, and its unique properties have made it a favorite among those who seek to harness its energy for personal growth and transformation.
Blue Zircon: A Stone of Clarity and Vitality
Blue zircon is often associated with clarity, vitality, and spiritual awakening. The gemstone is believed to enhance mental clarity and stimulate the intellect. It is also thought to promote vitality and energy, making it a popular choice for those seeking to boost their physical and mental well-being.
As one of the oldest minerals on Earth, blue zircon is often used in spiritual practices to connect with the Earth’s energy. Its vibrant blue color is said to resonate with the heart and throat chakras, promoting emotional balance and effective communication.
Care and Cleaning
Turquoise
- Cleaning: Use warm, soapy water and a soft brush. Avoid steam or ultrasonic cleaners.
- Storage: Store separately from other gemstones to prevent scratches.
- Avoid: Exposure to high heat, acids, and harsh chemicals.
- Maintenance: Reapply protective coatings periodically to maintain luster.
Turquoise is a soft gemstone, and its porous nature makes it susceptible to damage. Proper care is essential to preserve its beauty and durability.
Tanzanite
- Cleaning: Use warm, soapy water and a soft brush. Avoid steam or ultrasonic cleaners.
- Storage: Store in a cool, dry place away from direct sunlight.
- Avoid: Prolonged exposure to bright light, which can cause color fading.
- Maintenance: Handle with care to avoid scratches and abrasions.
Tanzanite is relatively durable but should be handled with care to prevent damage. Its pleochroic properties make it a unique and beautiful gemstone that requires proper care to maintain its vibrant colors.
Blue Zircon
- Cleaning: Use warm, soapy water and a soft brush. Avoid steam or ultrasonic cleaners.
- Storage: Store in a cool, dry place away from other gemstones to prevent scratching.
- Avoid: Abrasive conditions such as gardening, sports, or dishwashing.
- Maintenance: Handle with care to avoid abrasion and damage.
Blue zircon is a versatile gemstone that can be worn in a variety of settings. However, its hardness and stability make it suitable for everyday wear, provided it is handled with care.
Conclusion
December’s birthstones—turquoise, tanzanite, and blue zircon—each offer a unique blend of beauty, history, and symbolism. From the ancient protective powers of turquoise to the modern marvel of tanzanite and the versatile brilliance of blue zircon, these gemstones have captivated people for centuries. Whether used in jewelry, collected as treasures, or worn for their symbolic meanings, these stones continue to hold a special place in the world of gemology. Their rich histories, geological properties, and cultural significance make them not only beautiful but also deeply meaningful.