December, the final month of the year, is a time of celebration, reflection, and new beginnings. It marks the arrival of the winter solstice, the holiday season, and the end of another year. In the world of gemstones, December is unique due to the variety of birthstones it encompasses. These include turquoise, tanzanite, zircon (particularly blue zircon), and blue topaz. Each of these gemstones carries its own distinct history, symbolism, and gemological properties, making them not only beautiful but also rich in cultural and scientific significance.
This article delves into the December birthstones, exploring their origins, historical significance, physical properties, and practical care tips. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, this guide will provide you with a comprehensive understanding of these remarkable stones.
History and Lore
The tradition of birthstones dates back to ancient times, with roots in the Bible and early Jewish and European cultures. The earliest known reference to birthstones is found in the Breastplate of Aaron from the Book of Exodus, which lists twelve gemstones representing the twelve tribes of Israel. Over time, these stones were associated with different months of the year, and the tradition evolved into what we recognize today as birthstones.
December is one of the few months with multiple birthstones. Historically, ruby was considered the December birthstone, but over time, the list has expanded and changed. The modern list of December birthstones has evolved through several iterations:
- 1870: Turquoise was listed as the December birthstone in Tiffany & Co.’s “Gregorian Birthstone Poems” pamphlet.
- 1912: Turquoise remained as the primary December birthstone, with lapis lazuli as an alternative, according to the National Association of Jewellers.
- 1952: Zircon was added to the list by the Jewelry Industry Council of America.
- 2002: Tanzanite was added, making December the only month with four recognized birthstones.
Blue topaz was added as a modern alternative in the 20th century, particularly after the development of heat treatment methods that enhanced its blue color. Each of these stones has its own story and significance, contributing to the rich tapestry of December's gemstone heritage.
Geological Formation and Sources
Understanding the geological formation and sources of each December birthstone provides insight into their rarity, beauty, and value.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It forms in the oxidation zones of copper deposits and is often found in arid regions where it can be exposed to the surface. Turquoise is known for its vivid blue to greenish-blue color, which comes from the presence of copper and the degree of hydration.
Historically, turquoise was mined in ancient Persia, Egypt, and Afghanistan. In the modern era, significant sources include the Southwestern United States (Arizona and Nevada), Iran (Persian turquoise), and China. The quality and color of turquoise can vary widely depending on the location of the mine and the specific conditions under which the stone formed.
Tanzanite
Tanzanite is a variety of the mineral zoisite, with the chemical formula Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)₂·H₂O. It is known for its striking blue and violet hues, which result from the presence of vanadium and the way light interacts with the crystal structure.
Tanzanite is found exclusively in the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. It was discovered in 1967 and quickly became a popular gemstone due to its unique color and limited availability. The rarity of tanzanite, combined with its beauty, has made it a highly sought-after gemstone in the jewelry industry.
Zircon
Zircon is a silicate mineral with the chemical formula ZrSiO₄. It is known for its high refractive index and dispersion, which gives it a brilliant sparkle similar to that of diamonds. Zircon can be found in a variety of colors, including blue, yellow, red, and green. Blue zircon is the most common variety used in jewelry and is particularly associated with December.
Zircon is found in several parts of the world, including Sri Lanka, Cambodia, Myanmar, and Australia. The blue color of zircon is achieved through heat treatment, which removes the brown coloration and enhances the blue tones.
Blue Topaz
Blue topaz is a variety of the mineral topaz, with the chemical formula Al₂SiO₄(F,OH)₂. It is known for its hardness and clarity, making it a durable gemstone suitable for everyday wear. The blue color in blue topaz is typically achieved through irradiation and heat treatment, which enhances the natural color of the stone.
Blue topaz is found in several locations around the world, including Brazil, Nigeria, Sri Lanka, and China. Brazil is the largest producer of blue topaz. The development of treatment techniques in the 20th century made blue topaz more accessible and popular, leading to its inclusion as a modern December birthstone.
Gemological Properties
Each of the December birthstones has distinct gemological properties that contribute to its beauty, durability, and appeal in jewelry.
Turquoise
- Color: Ranges from deep blue to greenish-blue.
- Hardness: 5–6 on the Mohs scale.
- Clarity: Often has inclusions or matrix patterns.
- Luster: Waxy to subvitreous.
- Refractive Index: 1.61–1.65.
- Specific Gravity: 2.6–2.8.
Turquoise is relatively soft compared to other gemstones, making it prone to scratches and damage. It is also sensitive to chemicals and excessive moisture, which can cause discoloration or structural damage. Proper care is essential to maintain its appearance and longevity.
Tanzanite
- Color: Ranges from deep blue to violet.
- Hardness: 6–7 on the Mohs scale.
- Clarity: Often has inclusions.
- Luster: Vitreous.
- Refractive Index: 1.694–1.701.
- Specific Gravity: 3.3–3.4.
Tanzanite is known for its high refractive index and dispersion, giving it a brilliant sparkle. It is relatively durable but still requires careful handling to avoid chipping or cracking. Tanzanite is sensitive to heat and sudden temperature changes, which can cause it to fracture.
Zircon
- Color: Available in various colors, including blue, yellow, red, and green.
- Hardness: 6–7.5 on the Mohs scale.
- Clarity: Often has inclusions.
- Luster: Vitreous.
- Refractive Index: 1.92–2.01.
- Specific Gravity: 4.5–4.8.
Blue zircon is particularly popular for its high refractive index and dispersion, which give it a brilliant sparkle. It is relatively durable but can be brittle, making it prone to chipping. Proper care and appropriate jewelry settings are important to preserve its beauty.
Blue Topaz
- Color: Ranges from sky blue to London blue.
- Hardness: 8 on the Mohs scale.
- Clarity: Often has inclusions.
- Luster: Vitreous.
- Refractive Index: 1.62–1.64.
- Specific Gravity: 3.5–3.6.
Blue topaz is one of the harder December birthstones, making it ideal for everyday wear. It is known for its clarity and brilliance, and its popularity has increased due to the development of treatment methods that enhance its color. Blue topaz is relatively durable and requires minimal care to maintain its appearance.
Symbolism and Metaphysical Beliefs
In addition to their gemological properties, each of the December birthstones carries symbolic and metaphysical significance across different cultures and historical periods.
Turquoise
Turquoise has been revered for thousands of years and is considered a stone of protection, peace, and prosperity. It was used by ancient Egyptians, Persians, and Native American tribes, who believed it had healing and protective properties. In some cultures, turquoise was thought to ward off evil and bring good fortune.
Tanzanite
Tanzanite is associated with transformation, emotional healing, and spiritual awakening. It is believed to help balance emotions, enhance intuition, and promote inner peace. Tanzanite is also linked to the idea of new beginnings, making it a fitting birthstone for the end of the year.
Zircon
Zircon is associated with wisdom, clarity, and spiritual insight. It is believed to enhance memory, promote self-confidence, and provide protection during times of change. Zircon is also linked to the idea of transformation and is often used in meditation and spiritual practices.
Blue Topaz
Blue topaz is associated with calmness, clarity, and emotional balance. It is believed to promote serenity, soothe anxiety, and enhance communication. Blue topaz is also linked to the idea of love and friendship, making it a popular choice for jewelry that symbolizes relationships and connections.
Care and Cleaning
Proper care and cleaning are essential for maintaining the beauty and longevity of December’s birthstones. Each gemstone has specific care requirements based on its hardness, durability, and sensitivity to chemicals and environmental factors.
Turquoise
- Cleaning: Clean with a soft cloth and mild soap. Avoid using ultrasonic or steam cleaners.
- Storage: Store in a cool, dry place. Avoid exposure to direct sunlight and chemicals.
- Handling: Handle with care to avoid scratches and damage.
Tanzanite
- Cleaning: Clean with mild soap and water. Avoid ultrasonic or steam cleaners and sudden temperature changes.
- Storage: Store in a dry place away from direct sunlight.
- Handling: Handle with care to avoid chipping or cracking.
Zircon
- Cleaning: Clean with warm soapy water and a soft cloth. Avoid ultrasonic or steam cleaners.
- Storage: Store in a secure place to avoid chipping.
- Handling: Handle with care due to its brittleness.
Blue Topaz
- Cleaning: Clean with warm soapy water and a soft brush. Avoid exposure to heat and ultrasonic cleaners.
- Storage: Store in a cool, dry place.
- Handling: Handle with care to avoid scratches.
Jewelry Settings and Care Tips
Choosing the right jewelry setting is important for preserving the beauty and durability of each December birthstone. The ideal setting depends on the gemstone's hardness and durability.
- Blue Topaz: Works well in all types of settings, including prong, bezel, and pavé.
- Turquoise: Bezel settings are best for protecting its softer surface.
- Tanzanite: Choose protective settings like halos or bezels for rings.
- Zircon: Best suited for pendants or earrings where it is less likely to be knocked.
Proper care and appropriate settings help ensure that these gemstones remain beautiful and lasting treasures.
Conclusion
December is a unique and special month in the world of gemstones, offering a diverse selection of birthstones that include turquoise, tanzanite, zircon, and blue topaz. Each of these gemstones has its own distinct history, symbolism, and gemological properties, making them not only beautiful but also rich in cultural and scientific significance.
From the ancient traditions of turquoise to the modern popularity of blue topaz, the December birthstones reflect the evolving nature of gemstone appreciation and use. Whether you are selecting a December birthstone for yourself or as a gift, understanding the characteristics and care requirements of each stone can help you make an informed and meaningful choice.
As the year comes to a close, the December birthstones serve as a reminder of the beauty and richness of the natural world, as well as the enduring appeal of gemstones in human culture.