December, the final month of the year, is uniquely distinguished in the world of gemstones. Unlike most months, which are associated with a single birthstone, December is celebrated for having four: Blue Topaz, Turquoise, Tanzanite, and Zircon. Each of these gemstones is rich in history, symbolism, and physical properties, offering a diverse array of options for December-born individuals and gemstone enthusiasts alike. This article explores the origins, characteristics, cultural significance, and care tips for each of these four birthstones, drawing from authoritative sources and historical records to provide a comprehensive understanding of their role in jewelry and personal adornment.
Historical and Cultural Significance
The concept of birthstones has deep roots in both religious and cultural traditions. The earliest known references to birthstones appear in the Biblical Book of Exodus, where the High Priest’s breastplate was adorned with 12 stones representing the 12 tribes of Israel. Over time, these associations evolved, and by the 18th and 19th centuries, birthstones had become more widely recognized in Western culture. December, in particular, has seen multiple changes in its designated gemstones, reflecting shifting tastes and the discovery of new minerals.
In the early 19th century, Turquoise was the primary December birthstone, as documented in Tiffany & Co.'s Gregorian Birthstone Poems pamphlet of 1870. By the early 20th century, the National Association of Jewellers (now known as the Jewelers of America) listed both Turquoise and Lapis Lazuli as December’s stones. In 1952, Zircon was added to the list, and in 2002, Tanzanite—a relatively new discovery—was officially recognized as a December birthstone. Blue Topaz is also commonly associated with December, though its inclusion is sometimes considered modern or regional.
This evolution of December’s birthstones reflects the dynamic nature of gemstone traditions. As new gemstones are discovered and the cultural significance of older ones is reinterpreted, the list of December’s birthstones has expanded to include four distinct options. This diversity allows individuals to choose a gemstone that best aligns with their personal style, symbolic meaning, or even budget.
Geological Formation and Sources
Each of December’s birthstones is formed under unique geological conditions and is found in specific locations around the world. Understanding the origins of these gemstones provides insight into their rarity, coloration, and physical properties.
Blue Topaz
Blue Topaz is a relatively common gemstone, but its striking blue color is not natural. Most blue topaz is created through irradiation and heat treatment, which enhances or changes the color of naturally brown or yellow topaz. The raw material for topaz is typically mined in Brazil, where the majority of the world’s topaz supply originates. Smaller deposits are found in United States (Colorado and Texas), Mexico, and Nigeria.
Topaz is a silicate mineral with the chemical formula Al₂SiO₄(F,OH)₂. It is known for its hardness, ranking 8 on the Mohs scale, making it highly resistant to scratches. This durability makes Blue Topaz an excellent choice for everyday jewelry.
Turquoise
Turquoise is a phosphate mineral composed of copper, aluminum, and phosphorus with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It forms in arid, oxidized environments, typically in the cavities of volcanic rocks. The most famous source of turquoise is Iran, where it has been mined for thousands of years. Other significant sources include the United States (especially Arizona and New Mexico), Egypt, China, and Mexico.
Turquoise is relatively soft, with a Mohs hardness of 5 to 6, and is porous, which makes it sensitive to oils, acids, and prolonged exposure to moisture. For this reason, it is best suited for pendants, earrings, and brooches, rather than rings or bracelets that are worn more frequently.
Tanzanite
Tanzanite is one of the most unique gemstones in the world, as it is only found in one location: the Merelani Hills near Mount Kilimanjaro in Tanzania. Discovered in the 1960s, tanzanite is a trigonal mineral composed of columbite, with a chemical formula of Ca₂Al₃(SiO₄)₃(OH). Its characteristic violet-blue color is due to trace amounts of vanadium and iron, and it exhibits trichroism, meaning it can display three different colors depending on the angle of light.
Tanzanite has a Mohs hardness of 6 to 7, making it suitable for pendants, earrings, and rings with proper care. Due to its limited source and the relatively recent discovery, tanzanite is considered a rare and valuable gemstone, often associated with luxury and exclusivity.
Zircon
Zircon is one of the oldest minerals on Earth, with some crystals dating back over 4.4 billion years. It is a zirconium silicate with the chemical formula ZrSiO₄. Zircon is found in metamorphic and igneous rocks and is commonly mined in Australia, Brazil, Cambodia, and Madagascar.
Zircon is available in a wide range of colors, including blue, yellow, red, and colorless, but the most popular December variety is blue zircon, which is created through heat treatment. Blue zircon has a Mohs hardness of 6 to 7.5, making it relatively durable. It is known for its brilliant fire and refractive index, which is higher than that of diamonds, giving it a sparkling, rainbow-like effect.
Gemological Properties
Each of December’s birthstones has distinct physical and optical properties that make them unique in the world of gemstones. These properties influence not only their appearance but also their suitability for different types of jewelry.
Blue Topaz
- Color: Ranges from light blue to deep blue, often enhanced by treatment.
- Hardness: 8 on the Mohs scale.
- Refractive Index: 1.61–1.63.
- Luster: Vitreous.
- Transparency: Transparent to translucent.
- Cleavage: None (very durable).
- Specific Gravity: 3.53–3.54.
Turquoise
- Color: Blue to green, depending on the concentration of copper and iron.
- Hardness: 5–6 on the Mohs scale.
- Refractive Index: 1.61–1.65.
- Luster: Waxy to greasy.
- Transparency: Opaque to translucent.
- Cleavage: None.
- Specific Gravity: 2.72–2.85.
Tanzanite
- Color: Violet-blue to deep blue, with trichroism.
- Hardness: 6–7 on the Mohs scale.
- Refractive Index: 1.694–1.701.
- Luster: Vitreous.
- Transparency: Transparent.
- Cleavage: Poor (prone to chipping).
- Specific Gravity: 3.12–3.38.
Zircon
- Color: Blue, yellow, red, brown, and colorless (most common is blue zircon).
- Hardness: 6–7.5 on the Mohs scale.
- Refractive Index: 1.92–2.01 (very high).
- Luster: Vitreous.
- Transparency: Transparent to translucent.
- Cleavage: None.
- Specific Gravity: 4.6–4.8.
Symbolism and Metaphysical Beliefs
Gemstones have long been associated with metaphysical and spiritual properties, and December’s birthstones are no exception. These beliefs, while not scientifically validated, have been passed down through cultures and continue to influence how people perceive and use these stones.
Blue Topaz
- Symbolism: Clarity, communication, and emotional balance.
- Metaphysical Beliefs: Blue topaz is believed to promote mental clarity, emotional stability, and effective communication. It is also associated with protection from negative energy and is said to encourage truth and honesty in relationships.
Turquoise
- Symbolism: Protection, wisdom, and good fortune.
- Metaphysical Beliefs: Turquoise has been revered for centuries as a stone of protection, especially in ancient cultures like the Aztecs and Native Americans. It is also associated with healing, intuition, and spiritual awakening. In some traditions, it is used to attract good luck and prosperity.
Tanzanite
- Symbolism: Transformation, spiritual awareness, and emotional healing.
- Metaphysical Beliefs: Tanzanite is often linked to spiritual growth, emotional balance, and deep transformation. It is believed to help individuals release old patterns, embrace new beginnings, and connect with their higher self. It is also associated with courage and inner strength.
Zircon
- Symbolism: Wisdom, prosperity, and mental clarity.
- Metaphysical Beliefs: Zircon is considered a stone of wisdom and prosperity, especially in ancient and medieval traditions. It is believed to enhance intuition, mental clarity, and grounding, helping individuals make wise decisions and stay focused on their goals.
Care and Cleaning
Proper care is essential for maintaining the beauty and longevity of December’s birthstones. Each gemstone has specific care requirements based on its hardness, porosity, and sensitivity to heat and chemicals.
Blue Topaz
- Cleaning: Use mild soap and warm water with a soft brush. Avoid steam or ultrasonic cleaners, as they can cause damage.
- Storage: Store separately from other gemstones to avoid scratches.
- Avoid: Exposure to harsh chemicals and extreme temperature changes.
Turquoise
- Cleaning: Clean with soft cloths and mild soap. Avoid water immersion for extended periods.
- Storage: Keep in a dry place to prevent dulling or discoloration.
- Avoid: Exposure to acids, oils, and perfumes, which can damage the stone.
Tanzanite
- Cleaning: Use mild soap and water. Avoid steam and ultrasonic cleaners, as they can cause fractures or color changes.
- Storage: Store in a soft pouch to prevent chipping.
- Avoid: Exposure to strong light sources for long periods, which can fade the color.
Zircon
- Cleaning: Clean with warm soapy water. Avoid ultrasonic and steam cleaners, which can cause damage or fracture.
- Storage: Store in a separate compartment to prevent scratches.
- Avoid: Exposure to harsh chemicals and abrasive materials.
Conclusion
December’s four birthstones—Blue Topaz, Turquoise, Tanzanite, and Zircon—represent a rich tapestry of history, symbolism, and geology. Each gemstone has a unique story, from the ancient and sacred turquoise of the Old World to the newly discovered and rare tanzanite of Tanzania. Their inclusion in the December birthstone list reflects not only the diversity of the gemstone world but also the evolving nature of cultural traditions.
Whether chosen for their aesthetic appeal, spiritual significance, or durability, these stones offer something for every December-born individual. As gemstone enthusiasts and jewelry buyers continue to explore the world of birthstones, the enduring allure of these December gems remains as strong as ever.