December, the final month of the year, is celebrated with a unique richness in its selection of birthstones. Unlike most months, which are associated with a single gemstone, December is linked with multiple gemstones—each contributing its own distinct shade of blue to reflect the icy, tranquil, and mysterious nature of the season. These gemstones—tanzanite, turquoise, zircon, and blue topaz—offer a diverse array of colors, meanings, and properties. While they share a common blue color palette, each has its own geological background, cultural significance, and practical considerations for use in jewelry. This article explores the history, gemological properties, symbolic meanings, and care tips for each of these December birthstones, offering a comprehensive guide for gemstone enthusiasts, jewelry buyers, and students of gemology.
Introduction
December’s birthstones are celebrated for their cool, wintry hues and their unique histories. The selection includes tanzanite, turquoise, zircon, and blue topaz—each with its own charm and story. Tanzanite, the youngest of the group, was discovered in the 1960s in Tanzania and is known for its rare violet-blue color and trichroism. Turquoise, one of the oldest known gemstones, has been used for millennia across cultures and is associated with protection and spiritual clarity. Zircon, particularly the blue variety, is valued for its brilliance and historical use in ancient jewelry. Blue topaz, a modern addition, is favored for its durability and vibrant color. These gemstones not only reflect the winter season but also offer a range of options for jewelry, each with its own significance and care requirements.
History and Lore
Turquoise: An Ancient Gem of Protection
Turquoise is one of the oldest known gemstones, with evidence of its use dating back thousands of years. It has been revered by various civilizations, including the ancient Egyptians, who used it in their jewelry and amulets. Pharaohs like Tutankhamun were buried with turquoise-adorned items, symbolizing protection and spiritual connection. Native American cultures also hold turquoise in high regard, often using it in ceremonial jewelry and as a protective talisman. Its name, derived from the French word turquoise, which means "Turkish," reflects the trade routes through which the stone traveled to Europe. The robin’s-egg blue to greenish-blue color of turquoise has made it a popular choice for decorative and spiritual purposes.
Tanzanite: A Modern Discovery with Ancient Roots
Tanzanite is the youngest of the December birthstones, having been discovered in 1967 in Tanzania. Found in a small area near Mount Kilimanjaro, tanzanite is a variety of the mineral zoisite and is known for its rare violet-blue color and trichroic nature, meaning it can appear blue, purple, or burgundy depending on the angle of view. Named after its country of origin, tanzanite quickly gained popularity due to its beauty and rarity. It is considered one of the rarest gemstones in the world, as it is only found in that specific region. Tanzanite was added to the list of December birthstones in 2002, making it the most recent of the group.
Zircon: A Timeless Gemstone with a Sparkling History
Zircon has a long history of use in jewelry and has been prized for its brilliance and refractive properties. The blue variety of zircon, known as starlight blue zircon, is especially valued for its vibrant color and fire. Zircon has been used in ancient jewelry and was even mistaken for diamonds in the past due to its high refractive index and dispersion. The gemstone has been found in archaeological sites dating back thousands of years, indicating its long-standing appeal. Zircon is also known for its metaphysical properties, particularly its association with clarity and mental focus.
Blue Topaz: A Modern Addition with Natural and Treated Varieties
Blue topaz, a relatively recent addition to the list of December birthstones, is known for its vibrant blue color and durability. Unlike tanzanite and zircon, which are naturally blue, blue topaz is often created through heat treatment of colorless topaz. This process enhances its color and makes it more accessible for jewelry use. Blue topaz was officially added to the December birthstone list in the 20th century, and it has since become a popular choice for those seeking a durable and affordable blue gemstone. Its high hardness on the Mohs scale makes it suitable for everyday wear.
Geological Formation and Sources
Turquoise: A Product of Time and Chemistry
Turquoise is formed through the weathering of copper-bearing minerals in arid environments. It is typically found in the oxidation zones of copper deposits and is often associated with other minerals such as quartz, calcite, and iron oxides. The formation process involves the interaction of water, copper, and phosphorus, resulting in the characteristic blue to green-blue color of turquoise. Major sources of turquoise include the United States (particularly Arizona and New Mexico), China, Iran, and Egypt. The quality of turquoise varies depending on the presence of impurities such as iron and aluminum, which can affect its color and hardness.
Tanzanite: A Unique Geological Phenomenon
Tanzanite is formed under specific geological conditions that are unique to the region near Mount Kilimanjaro in Tanzania. The gemstone is created through the metamorphism of limestone, where the mineral zoisite undergoes changes due to high heat and pressure. The presence of vanadium and chromium impurities in the mineral structure gives tanzanite its distinctive violet-blue color. Because tanzanite is only found in this small area, it is considered one of the rarest gemstones in the world. The limited supply and high demand contribute to its value and desirability.
Zircon: A Versatile and Abundant Mineral
Zircon is a naturally occurring mineral that can be found in a variety of colors, including red, yellow, green, and blue. The blue variety of zircon, known as starlight blue zircon, is particularly popular in jewelry due to its vibrant color and brilliance. Zircon is found in many parts of the world, including Australia, Thailand, Cambodia, and the United States. The gemstone is often heat-treated to enhance its color and clarity. Unlike turquoise and tanzanite, zircon is relatively abundant and can be found in a range of qualities, making it a more accessible option for jewelry.
Blue Topaz: A Treatable Gem with Natural Origins
Blue topaz is a type of topaz that is naturally colorless or yellow. The blue color is achieved through heat treatment, which alters the color of the gemstone. This treatment is a common practice in the gemstone industry and is widely accepted as a method of enhancing the beauty of topaz. Blue topaz is found in various locations around the world, including Brazil, Mexico, Nigeria, and the United States. The United States designated blue topaz as the official state gem of Texas, recognizing its beauty and significance.
| Gemstone | Primary Sources | Formation Process |
|---|---|---|
| Turquoise | Arizona, New Mexico, Iran, Egypt | Weathering of copper-bearing minerals in arid environments |
| Tanzanite | Tanzania | Metamorphism of limestone with vanadium and chromium impurities |
| Zircon | Australia, Thailand, Cambodia, U.S. | Found in various geological environments; color enhanced via heat treatment |
| Blue Topaz | Brazil, Mexico, Nigeria, U.S. | Naturally colorless or yellow; blue achieved through heat treatment |
Gemological Properties
Turquoise: A Soft and Delicate Gem
Turquoise has a relatively low hardness on the Mohs scale, ranging from 5 to 6. This makes it a soft gemstone that is prone to scratches and damage if not handled carefully. It is also porous, which means it can absorb oils and dirt over time. The color of turquoise can vary from a bright blue to a greenish-blue, depending on the presence of impurities such as iron and aluminum. Turquoise is often stabilized with resins or waxes to improve its durability and luster.
Tanzanite: A Rare and Fragile Gem
Tanzanite has a hardness of 6 to 7 on the Mohs scale, making it relatively soft for a gemstone. It is also prone to cleavage, which means it can split along certain planes if struck with force. The trichroic nature of tanzanite, where it can appear blue, purple, or burgundy depending on the viewing angle, is one of its most unique characteristics. Tanzanite is often cut into cushion or oval shapes to enhance its color and minimize the risk of damage.
Zircon: A Brilliant and Durable Gem
Zircon has a hardness of 6 to 7.5 on the Mohs scale, making it more durable than turquoise and slightly more durable than tanzanite. It is known for its high refractive index and dispersion, which give it a brilliant and fiery appearance. Zircon is available in a range of colors, including red, yellow, green, and blue. The blue variety, known as starlight blue zircon, is particularly popular in jewelry due to its vibrant color and sparkle.
Blue Topaz: A Durable and Vibrant Gem
Blue topaz has a hardness of 8 on the Mohs scale, making it one of the most durable December birthstones. This high hardness makes it suitable for everyday wear and less prone to scratches and damage. Blue topaz is known for its vibrant blue color and clarity, which can range from pale blue to deep blue. Its durability and affordability have made it a popular choice for engagement rings and other jewelry pieces.
| Gemstone | Hardness (Mohs Scale) | Color Range | Special Properties |
|---|---|---|---|
| Turquoise | 5-6 | Blue, greenish-blue | Porous, soft, often stabilized |
| Tanzanite | 6-7 | Violet-blue, purple, burgundy | Trichroism, rare, prone to cleavage |
| Zircon | 6-7.5 | Red, yellow, green, blue | High refractive index, dispersion |
| Blue Topaz | 8 | Bright blue | Durable, affordable, often heat-treated |
Symbolism and Metaphysical Beliefs
Turquoise: A Stone of Protection and Clarity
Turquoise has long been associated with protection, healing, and spiritual clarity. In ancient Egypt, it was believed to have protective properties and was often used in amulets and burial masks. Native American cultures also use turquoise as a protective talisman, often incorporating it into ceremonial jewelry. In modern times, turquoise is still valued for its calming and grounding effects, making it a popular choice for those seeking emotional balance and mental clarity.
Tanzanite: A Stone of Transformation and Clarity
Tanzanite is associated with transformation, growth, and new beginnings. Its violet-blue color is often seen as a symbol of clarity and curiosity, making it a popular choice for those undergoing personal or spiritual changes. Tanzanite is also believed to promote emotional healing and balance, helping individuals navigate difficult transitions with grace and understanding. Its rarity and beauty make it a meaningful and powerful gemstone for those seeking change and renewal.
Zircon: A Stone of Clarity and Focus
Zircon, particularly the blue variety, is associated with mental clarity and focus. It is believed to enhance concentration, memory, and decision-making, making it a valuable tool for students and professionals. Zircon is also thought to have a calming effect on the mind, helping to reduce stress and anxiety. In some cultures, zircon is also believed to have protective properties, making it a versatile and powerful gemstone.
Blue Topaz: A Stone of Strength and Calm
Blue topaz is associated with strength, calm, and positive energy. It is believed to promote a sense of balance and harmony, helping individuals stay centered and grounded. Blue topaz is also associated with good fortune and success, making it a popular choice for those seeking motivation and inspiration. Its durability and vibrant color make it a practical and meaningful gemstone for everyday use.
Care and Cleaning
Turquoise: Gentle Handling and Avoidance of Harsh Chemicals
Turquoise is a soft and porous gemstone that requires gentle care to maintain its beauty. It should be kept away from harsh chemicals, perfumes, and lotions, as these can damage its surface. Turquoise jewelry should be stored separately to avoid scratches and should be cleaned with a soft cloth and mild soap and water. It is also important to avoid exposing turquoise to extreme temperatures or prolonged sunlight, as these can cause fading and drying.
Tanzanite: Protection from Heat and Mechanical Stress
Tanzanite is a relatively fragile gemstone that is prone to cleavage and heat sensitivity. It should be handled with care to avoid impact and sudden temperature changes. Tanzanite jewelry should be stored in a cool, dry place and should not be exposed to high temperatures or direct sunlight for extended periods. Cleaning tanzanite can be done with a soft cloth and mild soap and water, but it is best to avoid harsh chemicals and abrasive materials.
Zircon: Avoiding High Heat and Chemicals
Zircon is a durable gemstone, but it should still be handled with care to avoid damage. It is sensitive to high heat, which can cause it to lose its color or become brittle. Zircon should be stored in a cool, dry place and should be cleaned with a soft cloth and mild soap and water. It is important to avoid exposure to harsh chemicals and abrasive materials, as these can scratch or dull the gemstone’s surface.
Blue Topaz: Durable and Easy to Care for
Blue topaz is one of the most durable December birthstones, making it suitable for everyday wear. It can be cleaned with a soft cloth and mild soap and water, and it is generally safe to use ultrasonic and steam cleaners. Blue topaz should be stored separately from other gemstones to avoid scratches, and it should be kept away from harsh chemicals and abrasive materials. Its high hardness makes it easy to care for and maintain its brilliance over time.
Conclusion
December’s birthstones—tanzanite, turquoise, zircon, and blue topaz—each bring their own unique qualities to the winter month. From the ancient symbolism of turquoise to the rare and transformative nature of tanzanite, these gemstones offer a rich tapestry of colors, meanings, and histories. Their geological origins, gemological properties, and cultural significance make them valuable and meaningful choices for jewelry and personal adornment. Whether you are drawn to the soft and delicate beauty of turquoise, the vibrant and durable nature of blue topaz, or the brilliance of zircon, each December birthstone offers something special. With proper care and appreciation, these gemstones can be cherished for generations, serving as beautiful reminders of the magic of December and the enduring appeal of gemstones.