December is a month of winter wonder and festive cheer, and it is also associated with some of the most captivating and diverse birthstones in the gemstone world. The December birthstones include tanzanite, turquoise, zircon, and blue topaz—each offering a unique shade of blue, from deep cobalt to delicate robin’s egg. These gemstones have been cherished for centuries, not only for their stunning color and beauty but also for their historical significance, cultural symbolism, and metaphysical properties.
This article explores the December birthstones in detail, covering their geological origins, gemological properties, historical and cultural meanings, and care guidelines. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, this guide provides a comprehensive overview of the December birthstones and their enduring appeal.
Historical and Cultural Significance
Ancient Roots and Cultural Significance
The December birthstones have deep historical roots and have been valued across various civilizations. Turquoise, for example, is one of the oldest known December birthstones and has been treasured for millennia. Ancient Egyptians, Persians, and Native American cultures revered turquoise for its protective and spiritual properties. In ancient Egypt, turquoise was often used in jewelry and amulets, believed to bring health, good fortune, and protection. Native American cultures, particularly the Navajo and Zuni, also considered turquoise a sacred stone, often using it in ceremonial objects and jewelry to symbolize peace and spiritual connection.
Zircon, another December birthstone, has a long history of use in jewelry and decorative arts. During medieval times, zircon was believed to bring good luck, better sleep, and protection. In Greek mythology, zircon is sometimes referred to as "hyacinth," symbolizing rebirth and transformation. This connection adds a layer of mythological significance to zircon, making it a gemstone of both historical and symbolic value.
Tanzanite is the most modern of the December birthstones, discovered in 1967 in Tanzania. It quickly gained popularity due to its vibrant blue to violet color and its association with transformation and spiritual awakening. Tanzanite is often called the "Stone of Transformation" and is believed to enhance intuition and spiritual awareness.
Blue topaz, the most recent addition to the December birthstone list, is known for its calming blue hues and is associated with purity and positivity. While it is a relatively new addition to the list, blue topaz has a rich history in jewelry and decorative arts, often used for its clarity and brilliance.
Metaphysical Properties and Symbolism
Each of the December birthstones is associated with specific metaphysical properties and symbolic meanings. These beliefs have evolved over time and vary across different cultures.
Turquoise is believed to promote protection, good fortune, and spiritual connection. It is often used in meditation and spiritual practices to enhance intuition and inner peace. In Tibetan Buddhism, turquoise is worn in malas (meditation beads) to symbolize good luck and spiritual enlightenment.
Tanzanite is associated with transformation, communication, and spiritual awareness. It is believed to help individuals communicate more effectively and with compassion, especially in resolving conflicts and fostering deeper connections. Tanzanite is also known as the "Stone of Magic" due to its unique color and transformative properties.
Zircon has been historically linked to good luck, better sleep, and protection. In modern times, zircon is associated with success, wisdom, and positivity. Different colors of zircon carry their own meanings—white zircon symbolizes purity, while yellow zircon is known as the "Stone of Prosperity."
Blue Topaz is associated with purity, calmness, and positive energy. It is believed to promote emotional stability and enhance creativity. Blue topaz is often used in jewelry to symbolize clarity and serenity.
Geological Formation and Sources
Origin and Formation
The December birthstones are formed through various geological processes, resulting in their unique colors and properties.
Tanzanite is a type of zoisite and is found only in Tanzania, near the base of Mount Kilimanjaro. It was discovered in 1967 and quickly became a popular gemstone due to its vibrant blue to violet color. Tanzanite is formed under high-pressure and high-temperature conditions, which give it its distinctive color.
Turquoise is a hydrated phosphate of aluminum and copper. It is typically found in arid regions and forms in the oxidation zones of copper deposits. The United States, particularly Arizona, New Mexico, and Nevada, are known for their high-quality turquoise deposits. Other notable sources include Iran, China, and Egypt.
Zircon is a silicate mineral that occurs in various colors, including blue, yellow, red, and colorless. Blue zircon is often heat-treated to enhance its color. Zircon is found in many parts of the world, including Sri Lanka, Australia, Myanmar, Vietnam, and Cambodia. It is known for its durability and brilliance, making it a popular gemstone for jewelry.
Blue Topaz is a variety of topaz that is known for its clear blue color. It is often heat-treated to enhance or alter its color. Blue topaz is found in various locations around the world, including Brazil, Nigeria, and the United States. It is one of the most affordable and versatile gemstones, often used in a wide range of jewelry designs.
Mining and Availability
The availability of December birthstones is influenced by their geographic distribution and mining practices. Tanzanite is exclusive to Tanzania, making it a rare and valuable gemstone. Turquoise is found in several countries, but high-quality turquoise is relatively rare and highly sought after. Zircon is more widely available, with deposits in multiple countries, but the most valuable zircons are often heat-treated to enhance their color. Blue topaz is the most abundant of the December birthstones and is available in a wide range of qualities and sizes.
Gemological Properties
Key Properties of the December Birthstones
Each of the December birthstones has unique gemological properties that influence their appearance, durability, and use in jewelry.
| Gemstone | Color | Hardness (Mohs) | Chemical Composition | Refractive Index | Cleavage | Transparency | Treatments |
|---|---|---|---|---|---|---|---|
| Tanzanite | Blue to violet | 6–7 | Calcium aluminum silicate | 1.694–1.701 | Perfect in one direction | Transparent to translucent | Heat treatment |
| Turquoise | Blue to green | 5–6 | Hydrated phosphate of aluminum and copper | 1.61–1.65 | Uneven | Opaque to translucent | Stabilization, dyeing |
| Zircon | Blue, yellow, red, colorless | 6–7.5 | Zirconium silicate | 1.92–2.01 | Perfect in two directions | Transparent to translucent | Heat treatment |
| Blue Topaz | Blue | 8 | Aluminum silicate | 1.61–1.63 | None | Transparent | Heat treatment |
Tanzanite
Tanzanite has a hardness of 6–7 on the Mohs scale, making it relatively durable but not as hard as some other gemstones. Its chemical composition is calcium aluminum silicate, and it has a refractive index of 1.694–1.701. Tanzanite has perfect cleavage in one direction, which means it can be prone to chipping if not handled carefully. Tanzanite is typically heat-treated to enhance its color, making it one of the most popular treatments in gemstone processing.
Turquoise
Turquoise has a hardness of 5–6 on the Mohs scale and is relatively soft compared to other gemstones. It is a hydrated phosphate of aluminum and copper, with a refractive index of 1.61–1.65. Turquoise has an uneven cleavage and is opaque to translucent. It is often stabilized with resins or dyes to enhance its color and durability. Stabilized turquoise is more commonly used in jewelry to prevent it from drying out and cracking.
Zircon
Zircon has a hardness of 6–7.5 on the Mohs scale and is known for its brilliance and refractive index of 1.92–2.01. Zircon has perfect cleavage in two directions, making it susceptible to chipping. It is often heat-treated to produce blue and colorless varieties, as well as orange, yellow, and red. Heat-treated zircon is more commonly used in jewelry due to its enhanced color and clarity.
Blue Topaz
Blue topaz has a hardness of 8 on the Mohs scale, making it one of the hardest December birthstones. It is an aluminum silicate with a refractive index of 1.61–1.63. Blue topaz has no cleavage, making it very durable and suitable for everyday wear. It is often heat-treated to enhance or alter its color, making it a popular choice for affordable and versatile jewelry.
Care and Cleaning
Proper Maintenance of December Birthstones
Proper care and cleaning are essential to maintain the beauty and longevity of the December birthstones. Each gemstone has specific care requirements based on its hardness, cleavage, and sensitivity to chemicals and light.
Tanzanite
Tanzanite should be cleaned with a soft brush and mild soap in warm water. Avoid using ultrasonic or steam cleaners, as they can damage the gemstone. Tanzanite should be protected from hard knocks and high temperatures, as it can be prone to chipping. It is best to avoid wearing tanzanite in rough conditions, such as while gardening, playing sports, or doing dishes.
Turquoise
Turquoise is relatively soft and should be handled with care. It should be cleaned with a soft brush and mild soap in warm water. Avoid using ultrasonic or steam cleaners, as they can damage the gemstone. Turquoise should be protected from heat, dry environments, and harsh chemicals, as it can dry out and crack. Stabilized turquoise is more durable but should still be handled with care to maintain its color and integrity.
Zircon
Zircon should be cleaned with a soft brush and mild soap in warm water. Avoid using ultrasonic or steam cleaners, as they can damage the gemstone. Zircon has perfect cleavage in two directions, making it susceptible to chipping. It is best to avoid wearing zircon in rough conditions and to protect it from hard knocks and high temperatures.
Blue Topaz
Blue topaz is one of the hardest December birthstones and is relatively durable. It can be cleaned with a soft brush and mild soap in warm water. It is safe to use ultrasonic and steam cleaners, but it is best to avoid harsh chemicals and high temperatures. Blue topaz is suitable for everyday wear and can withstand normal wear and tear.
Conclusion
The December birthstones—tanzanite, turquoise, zircon, and blue topaz—offer a stunning array of blue hues, each with its own unique charm and significance. These gemstones have a rich history of use in jewelry, decorative arts, and spiritual practices, making them treasured possessions for December-born individuals and gemstone enthusiasts alike. Whether you are drawn to the deep blue of tanzanite, the vibrant turquoise hues, the brilliance of zircon, or the calming blue of topaz, there is a December birthstone to suit every taste and preference. Understanding the geological properties, historical significance, and care requirements of these gemstones can help you appreciate their beauty and value for years to come.