December, the final month of the year, is symbolically rich with celebration, transition, and renewal. Among its many symbolic associations, it also holds the distinction of being one of the few months with multiple birthstones. The December birthstones include Blue Zircon, Blue Topaz, Tanzanite, Lapis Lazuli, and Turquoise. These gemstones, each with their own unique color, history, and symbolism, offer a compelling range of options for jewelry and personal adornment. This article explores the historical, geological, and cultural significance of these stones, their gemological properties, and how to care for them.
A Historical and Cultural Overview
The tradition of associating gemstones with months of the year is ancient, with roots in biblical texts and medieval European practices. The earliest references to birthstones appear in the Bible’s Book of Exodus, where the twelve stones on Aaron’s breastplate are said to represent the twelve tribes of Israel. Over centuries, these associations evolved into a system linking each month with specific gemstones.
For December, the list has evolved significantly over time. In 1870, Turquoise was designated as the December birthstone by Tiffany & Co. in their "Gregorian Birthstone Poems" pamphlet. By 1912, the National Association of Jewellers (now the Jewellers of America) listed Turquoise as the primary December birthstone and Lapis Lazuli as an alternative. In 1952, Zircon was added to the list by the Jewelry Industry Council of America, and in 2002, Tanzanite was officially recognized as a December birthstone.
By the 21st century, the list had expanded to include Blue Topaz as a modern alternative, reflecting the growing appreciation for blue-colored gemstones and the desire to offer a range of options in terms of color, price, and symbolic meaning.
This multiplicity of December birthstones speaks to both the gemstone trade’s adaptability and the cultural richness of December itself—a month that marks the end of the year and the beginning of a new one, associated with themes of change, reflection, and hope.
Geological Formation and Sources
Each December birthstone is formed through unique geological processes and is sourced from specific parts of the world, which adds to their individuality and rarity.
Blue Zircon
Blue Zircon is a type of zircon that has been heat-treated to enhance its blue color. Zircon is one of the oldest minerals on Earth, with some specimens dating back over 4 billion years. Natural zircon occurs in a variety of colors, including red, yellow, and brown, but the blue variety is created through controlled heating in the range of 700–900°C.
Zircon is found in metamorphic and igneous rocks and is often mined in countries such as Australia, Brazil, Madagascar, and Myanmar. It is known for its high refractive index and strong dispersion, which gives it a brilliant, fire-like appearance. Blue Zircon has a Mohs hardness of 6.5–7.5, making it durable enough for everyday wear in jewelry.
Blue Topaz
Blue Topaz is a colorless mineral that is irradiated and heat-treated to produce a blue color. The most popular shade is a sky-blue or London blue, but variations exist. Topaz is composed of silicic acid and is one of the hardest gemstones, with a Mohs hardness of 8, which makes it highly resistant to scratches and suitable for rings and bracelets.
Topaz is typically found in igneous rocks and is mined in Brazil, Mexico, Russia, and USA. The gemstone is also prized for its clarity and brilliance, and it is often cut in a wide range of styles, including brilliant and oval cuts.
Tanzanite
Tanzanite is a rare gemstone discovered in 1967 near Mount Kilimanjaro in Tanzania. It is a type of cushion-shaped zoisite that is heat-treated to enhance its blue-violet color. Tanzanite has a Mohs hardness of 6–7, which makes it suitable for most types of jewelry, though it requires careful handling due to its perfect cleavage.
The gemstone’s deep, velvety color and trichroism (the ability to display three different colors when viewed from different angles) make it highly desirable. Tanzanite is also associated with a sense of rarity and exclusivity, as it is only found in one location on Earth.
Lapis Lazuli
Lapis Lazuli is not a gemstone in the traditional sense but a metamorphic rock composed of lazurite, pyrite, and calcite. It is known for its deep blue color with golden flecks of pyrite and white calcite veins. The most prized lapis lazuli comes from Afghanistan, where it has been mined for thousands of years.
Lapis lazuli has a Mohs hardness of 5–6, making it more fragile than most gemstones. It is often used in carvings, inlay work, and for beads and cabochons in jewelry. Its rich blue color has been associated with wisdom, truth, and spiritual enlightenment in many ancient cultures.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper. It is formed in arid regions where copper-rich minerals are exposed to weathering and water. It is known for its characteristic blue-green color and is often found with veins and matrix patterns that add to its natural beauty.
Turquoise is mined in the United States (especially Arizona, New Mexico, and Nevada), China, Nepal, Egypt, and Iran. It has a Mohs hardness of 5–6, making it relatively soft and requiring gentle handling and care.
Gemological Properties
The gemological properties of each December birthstone contribute to their allure and suitability for different types of jewelry.
| Gemstone | Chemical Composition | Color | Hardness (Mohs) | Cleavage | Refractive Index | Transparency |
|---|---|---|---|---|---|---|
| Blue Zircon | ZrSiO₄ | Blue | 6.5–7.5 | Distinct | 1.92–2.01 | Transparent |
| Blue Topaz | Al₂SiO₄(F,OH)₂ | Blue | 8 | Indistinct | 1.62–1.63 | Transparent |
| Tanzanite | Ca₂Al₃(PO₄)₃(OH)₃·H₂O | Blue to Violet | 6–7 | Perfect | 1.694–1.701 | Transparent |
| Lapis Lazuli | Lazurite (Na,Ca)₈(Al,Si)₆O₂₀(S,SO₄,C)Cl₂·H₂O | Deep Blue | 5–6 | Indistinct | 1.5–1.7 | Opaque |
| Turquoise | AlPO₄·3H₂O | Blue-Green | 5–6 | Indistinct | 1.61–1.66 | Translucent |
These properties affect how each gemstone is best used in jewelry. For example, Blue Topaz is an excellent choice for rings due to its hardness and durability, while Tanzanite and Lapis Lazuli are better suited for pendants and earrings where they are less likely to be subjected to abrasion or impact.
Symbolism and Metaphysical Beliefs
Each December birthstone is associated with various symbolic and metaphysical properties that have been passed down through history and continue to influence modern beliefs.
Blue Zircon
Zircon has long been associated with wisdom, fearlessness, and good fortune. Its brilliance and fire are believed to enhance clarity of thought and emotional balance. In ancient times, zircon was believed to have protective properties, guarding the wearer against harm and negative energies.
Blue Topaz
Blue Topaz is often linked to serenity, calmness, and emotional stability. It is believed to promote a sense of inner peace and help in overcoming anxiety and stress. Some traditions also associate it with healing and protection, especially for the heart and throat chakras.
Tanzanite
Tanzanite is known for its spiritual properties, particularly its ability to enhance intuition, empathy, and emotional healing. It is considered a stone of transformation, aiding in the release of old patterns and the acceptance of new possibilities. Tanzanite is also associated with harmony, love, and compassion.
Lapis Lazuli
Lapis lazuli is one of the most historically significant December birthstones. It has been associated with wisdom, truth, and spiritual enlightenment for thousands of years. It is believed to enhance intellectual abilities, stimulate creativity, and promote inner peace. In ancient Egypt, lapis lazuli was considered a stone of royalty, worn by pharaohs and used in sacred rituals.
Turquoise
Turquoise is one of the most versatile and culturally significant December birthstones. It has been used as a protective talisman, amulet, and good-luck charm in many cultures, including those of the Ancient Egyptians, Native Americans, and Persians. It is believed to bring protection, good fortune, and inner calm. In Native American traditions, it is also associated with healing and divine communication.
Care and Cleaning
Proper care is essential to preserve the beauty and integrity of December birthstones. Here are some guidelines for each gemstone:
Blue Zircon
- Avoid exposure to high heat and sunlight, which can cause fading.
- Clean with a soft cloth and mild soap solution.
- Avoid using ultrasonic cleaners or steamers, which can cause internal stress.
Blue Topaz
- Can be cleaned with warm, soapy water and a soft brush.
- Ultrasonic and steam cleaners are safe for Blue Topaz.
- Avoid exposure to harsh chemicals and abrasives.
Tanzanite
- Tanzanite should be cleaned with a soft cloth and mild soap.
- Avoid exposure to high heat and direct sunlight, which can cause fading.
- Avoid using steam or ultrasonic cleaners.
Lapis Lazuli
- Lapis lazuli is soft and porous, so it requires gentle cleaning with a damp cloth.
- Avoid exposure to water, oils, and acidic substances, which can damage the surface.
- Store separately from harder gemstones to avoid scratching.
Turquoise
- Turquoise is porous and sensitive to water and oils.
- Clean with a dry or slightly damp cloth only.
- Avoid exposing to direct sunlight, as it can cause fading.
- Store in a cool, dry place away from other gemstones.
Conclusion
The December birthstones—Blue Zircon, Blue Topaz, Tanzanite, Lapis Lazuli, and Turquoise—offer a rich tapestry of history, symbolism, and beauty. Each gemstone carries its own unique story, from the ancient civilizations that revered lapis lazuli to the modern appreciation for tanzanite’s rarity and brilliance. Whether chosen for its color, meaning, or durability, a December birthstone is more than just a piece of jewelry—it is a connection to the past, a symbol of individuality, and a reflection of the wearer’s personality.
By understanding the gemological properties, historical significance, and proper care of these stones, one can appreciate their true value and make informed choices when selecting or wearing them. As with any fine jewelry, a December birthstone is best treated with care and respect, ensuring that it remains a cherished heirloom for generations to come.