December is a month of celebration, marked by the arrival of the winter season and the joy of the holidays. It is also a time to honor the unique beauty of the December birthstones—turquoise, tanzanite, and zircon. These gemstones, each with its own distinct color, history, and symbolism, offer a rich tapestry of meaning and aesthetic appeal that makes them ideal for jewelry and personal adornment.
This article provides a comprehensive overview of the December birthstones, focusing on their historical significance, gemological properties, cultural symbolism, and practical considerations for care and use in jewelry. Drawing from a variety of sources, it explores how these stones have been valued across time and how they continue to inspire designers and jewelry lovers today.
History and Lore
The tradition of associating specific gemstones with birth months dates back centuries, with roots in ancient civilizations such as the Greeks, Romans, and even the Norse. The concept of birthstones is thought to have originated from the twelve stones mentioned in the biblical Breastplate of Aaron, described in Exodus 39. Over time, various cultures added their own interpretations, and the list of birthstones has evolved, sometimes incorporating new discoveries.
For December, the birthstones have changed over time. The earliest known December birthstone was turquoise, a gemstone that has been prized for thousands of years. Turquoise was used in ancient Egypt, Mesoamerica, and the American Southwest, often for its vibrant blue-green hue and the protective properties attributed to it.
In 1952, tanzanite was added to the list of December birthstones. Discovered in Tanzania in 1967, tanzanite is a relatively modern gemstone that quickly gained popularity due to its striking color and limited availability—being found only in the Merelani Hills near Arusha, Tanzania.
Zircon, the third December birthstone, has a longer history than the others. Zircon has been used in jewelry for centuries and is known for its brilliance and refractive properties. However, it was only officially recognized as a December birthstone in more recent decades, likely in the late 20th century.
These three gemstones—turquoise, tanzanite, and zircon—each contribute to the rich tradition of December birthstone jewelry, offering a variety of styles, colors, and meanings to choose from.
Geological Formation and Sources
The geological formation of each December birthstone is unique, reflecting the natural processes that create these beautiful gems.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, with the chemical formula Al₂(OH)₃PO₄·4H₂O. It forms in the oxidized zones of copper deposits, where water and chemical reactions contribute to its color and structure. The presence of copper gives turquoise its characteristic blue-green hues, while the presence of iron can produce more green tones.
Turquoise is found in arid regions with specific geological conditions, such as the American Southwest (including Arizona and New Mexico), as well as in Iran, Egypt, and China. The American Southwest, in particular, is known for producing high-quality turquoise with distinct matrix patterns—organic veins and spots that add to the stone’s visual appeal.
Tanzanite
Tanzanite is a type of columbite-zircon, a mineral that is part of the zircon family. Its chemical formula is Ca₂Al₃Si₃O₁₂(OH)₂, and it is known for its trichroic nature, meaning it can exhibit three different colors when viewed from different angles: blue, purple, and brown. Tanzanite’s blue color is due to the presence of vanadium, a trace element that is relatively rare in nature.
Tanzanite is found only in the Merelani Hills of Tanzania, near the city of Arusha. This limited geographic source makes tanzanite a rare and valuable gemstone. The stone is often heat-treated to enhance its color, bringing out the vivid blue and purple tones that make it so desirable.
Zircon
Zircon is a mineral composed of zirconium silicate (ZrSiO₄) and is known for its high refractive index and brilliance. Zircon occurs in a wide range of colors, including blue, red, yellow, and green, but the most popular zircon for December birthstone jewelry is the blue variety.
Blue zircon is typically heat-treated to transform its natural color into a vibrant blue. This treatment is stable and does not affect the stone’s durability. Zircon is found in various parts of the world, including Thailand, Cambodia, Sri Lanka, and parts of Africa. It is often mistaken for cubic zirconia, a synthetic gemstone, but natural zircon is much older and has a different chemical composition and refractive properties.
Gemological Properties
Understanding the gemological properties of the December birthstones is essential for both jewelry enthusiasts and professionals. These properties determine the stone’s appearance, durability, and suitability for different types of jewelry.
Turquoise
- Color: Ranges from blue to green, often with brown or black matrix patterns.
- Hardness: 5–6 on the Mohs scale, relatively soft compared to other gemstones.
- Luster: Waxy or greasy.
- Transparency: Usually opaque or translucent.
- Refractive Index: 1.61–1.65.
- Specific Gravity: 2.6–2.8.
Turquoise is best suited for jewelry that is not subjected to frequent wear or impact, such as pendants and earrings. Due to its relatively low hardness, it should be protected from abrasion and moisture.
Tanzanite
- Color: Deep blue to violet, with trichroism.
- Hardness: 6–7 on the Mohs scale, more durable than turquoise.
- Luster: Vitreous.
- Transparency: Transparent to translucent.
- Refractive Index: 1.694–1.701.
- Specific Gravity: 3.10–3.40.
Tanzanite is a versatile gemstone that can be used in a variety of jewelry styles, including rings, earrings, and pendants. Its durability makes it suitable for daily wear, although it should still be handled with care to avoid scratches and chips.
Zircon
- Color: Available in a range of colors, but blue is the most popular for December birthstone jewelry.
- Hardness: 6–7.5 on the Mohs scale, with some varieties reaching up to 8.
- Luster: Vitreous to subadamantine.
- Transparency: Transparent.
- Refractive Index: 1.92–2.01.
- Specific Gravity: 4.6–4.7.
Zircon is known for its high refractive index, which gives it a brilliant sparkle. The blue variety is particularly popular and is often used in rings, earrings, and pendants. Its durability makes it a good choice for everyday wear.
Symbolism and Metaphysical Beliefs
Each of the December birthstones carries its own unique symbolism and metaphysical properties, which have been attributed to them across different cultures and time periods.
Turquoise
Turquoise has long been associated with protection, healing, and wisdom. In ancient times, it was believed to ward off evil spirits and bring good luck. Native American cultures, particularly the Navajo and Zuni, have used turquoise in jewelry and ceremonial objects for centuries, considering it a sacred stone that connects the earth and the sky.
In modern times, turquoise is still valued for its calming and soothing properties. It is believed to promote emotional stability, enhance communication, and encourage honesty. Some people wear turquoise as a talisman to help with intuition and spiritual insight.
Tanzanite
Tanzanite is associated with transformation, spiritual growth, and emotional healing. It is believed to help individuals release old patterns and embrace new beginnings. The stone is also thought to enhance self-awareness, compassion, and emotional balance.
Due to its connection with the heart chakra, tanzanite is often used in meditation and spiritual practices. It is believed to open the heart to love and understanding, making it a popular choice for those seeking emotional healing and personal growth.
Zircon
Zircon is associated with strength, courage, and vitality. In ancient times, it was believed to provide protection and promote good health. Some cultures considered zircon a stone of fertility and prosperity, and it was often used in talismans and amulets.
Modern metaphysical beliefs attribute zircon with enhancing energy, boosting confidence, and promoting clarity of thought. It is also believed to help individuals overcome obstacles and achieve their goals.
Care and Cleaning
Proper care and cleaning are essential for maintaining the beauty and longevity of December birthstone jewelry. Each gemstone has specific requirements based on its hardness, luster, and sensitivity to certain substances.
Turquoise
- Cleaning: Use a soft, damp cloth to gently wipe the surface. Avoid using harsh chemicals, ultrasonic cleaners, or steam cleaners, as these can damage the stone or remove its natural luster.
- Storage: Store turquoise separately from other gemstones to prevent scratching. Keep it in a dry, cool place to prevent dehydration and cracking.
- Moisture Sensitivity: Turquoise can absorb moisture, so it is best to remove it before swimming or bathing.
Tanzanite
- Cleaning: Use a mild soap and warm water solution with a soft cloth or a soft-bristled brush to clean the stone. Avoid ultrasonic cleaners, as they can cause damage.
- Storage: Store tanzanite in a soft pouch or box to prevent scratches. Keep it away from direct sunlight, as prolonged exposure can cause the color to fade.
- Heat Sensitivity: Tanzanite is heat-treated to enhance its color, so it should not be exposed to high temperatures.
Zircon
- Cleaning: Use a mild soap and warm water solution with a soft cloth or brush. Avoid using ultrasonic cleaners, as they can cause the stone to crack.
- Storage: Store zircon in a soft pouch to prevent scratching. It can be stored with other gemstones, as it is relatively durable.
- Heat Sensitivity: Zircon is often heat-treated to enhance its color, so it should not be exposed to high temperatures.
Conclusion
The December birthstones—turquoise, tanzanite, and zircon—offer a unique combination of beauty, symbolism, and historical significance. Whether you are choosing jewelry for yourself or as a gift for a loved one, these gemstones provide a rich and meaningful option for December birthdays.
From the ancient protective powers of turquoise to the transformative energy of tanzanite and the vibrant brilliance of zircon, each stone tells its own story. Understanding their gemological properties, sources, and symbolism allows for a deeper appreciation of these remarkable gemstones.
As you explore the world of December birthstone jewelry, you will find a wide range of styles, from classic to contemporary, that celebrate the enduring appeal of these stones. Whether worn as a necklace, ring, or bracelet, December birthstone jewelry is a lasting tribute to the beauty and meaning of these special gems.