December, the final month of the year, is marked by the arrival of winter, the celebration of the Winter Solstice, and the anticipation of New Year’s. It is also a month rich in gemological significance, as it is one of the few months associated with three official birthstones: turquoise, tanzanite, and zircon, with blue topaz often included in modern interpretations. These gemstones, each distinct in appearance and history, carry a wealth of cultural, spiritual, and geological significance that has endured across centuries.
In this article, we explore the history, properties, cultural symbolism, and modern relevance of December’s birthstones. We delve into their geological formation, sources, and metaphysical attributes, offering insights that will appeal to gemstone enthusiasts, jewelry buyers, and students of gemology.
Historical and Cultural Significance
The concept of birthstones has ancient roots, often linked to religious and cultural traditions. While December's modern birthstone list includes multiple stones, its designation as a month with three or four options is a relatively recent development. The earliest known birthstone lists, such as those from biblical and medieval traditions, assigned a single gemstone—ruby—to December.
However, by the 19th and 20th centuries, the birthstone list began to evolve to reflect both scientific discoveries and aesthetic preferences. The following timeline highlights the key additions to December’s birthstone roster:
- 1870: Turquoise was first designated as a December birthstone by Tiffany & Co.
- 1912: The National Association of Jewellers (now the American Gem Society) listed turquoise as the primary December birthstone and lapis lazuli as an alternative.
- 1952: Zircon was added to the list by the Jewelry Industry Council of America.
- 2002: Tanzanite, a newly discovered gemstone from Tanzania, was officially added to the modern December birthstone list.
Blue topaz, while not traditionally listed in the 20th-century lists, has gained popularity in modern times and is frequently cited as a December birthstone due to its durability and vibrant blue hues.
The inclusion of multiple stones for December reflects the desire to provide a range of options for different tastes, budgets, and jewelry styles. Turquoise, in particular, has a long and revered history, especially among ancient cultures such as the Egyptians, Persians, and Native Americans, who valued it for its protective and spiritual properties.
Geological Formation and Sources
Understanding the geological background of a gemstone provides insight into its rarity, durability, and aesthetic appeal. Each of December’s birthstones forms under unique conditions and is found in specific geographic regions.
Turquoise
Turquoise is a phosphate mineral that forms in anhydrous environments, typically in cavities of volcanic rocks where water has transported and deposited copper and phosphate compounds. It is often found in association with copper deposits and is commonly mined in dry, arid regions.
Key sources of turquoise include:
- Iran – Known for producing high-quality, deep-blue turquoise with minimal matrix (the web-like mineral inclusions).
- United States – Particularly Arizona, New Mexico, and Nevada, which are famous for their turquoise mining and traditional Native American jewelry.
- Tibet and India – Historically significant sources, where turquoise was used as currency and in religious artifacts.
Turquoise is relatively soft, with a Mohs hardness of 5–6, making it more susceptible to damage than harder gemstones. It is also sensitive to moisture, heat, and acidic substances, which can cause it to lose color or become brittle.
Tanzanite
Tanzanite is a trigonal mineral that forms from the transformation of zoisite under high heat and pressure. It is unique to Tanzania, having been first discovered in 1967 by a Masai herdsman near the Serengeti Plains.
Its pleochroic nature—meaning it can display different colors under different angles of light—makes it visually striking. Tanzanite typically shows violet-blue, deep blue, and purplish-red hues.
Tanzanite is rare and is considered one of the most geographically limited gemstones, as it is found only in a small area of Tanzania. It has a Mohs hardness of 6–7, making it relatively durable, though still fragile compared to harder gems like diamonds or sapphires.
Zircon
Zircon is a zirconium silicate that has been around since the Archean Eon, making it one of the oldest minerals on Earth. It forms in metamorphic and igneous rocks and is known for its brilliance and refractive index, often rivaling that of diamonds.
The blue zircon used as a December birthstone is typically heat-treated to enhance its color. Zircon occurs in various colors, but the blue variety is the most popular in jewelry.
Significant sources of zircon include:
- Australia
- Madagascar
- India
- Brazil
Zircon has a Mohs hardness of 6.5–7.5, making it more durable than turquoise and slightly harder than tanzanite. It is also resistant to heat and light, which makes it a popular choice for engagement rings and daily wear.
Blue Topaz
Blue topaz, though not always listed as a traditional December birthstone, has become a popular modern alternative due to its durability and affordability. It is created through irradiation and heat treatment of yellow or brown topaz, resulting in a vibrant blue hue.
Blue topaz is known for its transparency, clarity, and brilliance, and it is one of the hardest December birthstones, with a Mohs hardness of 8. This makes it ideal for rings, bracelets, and pendants, as it is less likely to chip or scratch in daily wear.
Major sources of topaz include:
- Brazil
- Myanmar
- Russia
- United States
Gemological Properties
Understanding the physical and optical properties of a gemstone is essential for identifying, purchasing, and caring for it. Below is a detailed comparison of the four most commonly associated December birthstones.
| Gemstone | Color | Mohs Hardness | Chemical Composition | Refractive Index | Cleavage/ Fracture | Transparency |
|---|---|---|---|---|---|---|
| Turquoise | Sky blue, greenish-blue | 5 – 6 | Hydrated phosphate of aluminum and copper | 1.61 – 1.65 | Uneven fracture | Translucent |
| Tanzanite | Violet-blue, purplish-red | 6 – 7 | Calcium aluminum silicate | 1.694 – 1.700 | Indistinct cleavage | Transparent |
| Zircon | Brilliant blue (heat-treated) | 6.5 – 7.5 | Zirconium silicate | 1.92 – 2.01 | Perfect cleavage in some | Transparent |
| Blue Topaz | Sky blue, Swiss blue, London blue | 8 | Silica and aluminum | 1.61 – 1.63 | No cleavage | Transparent |
These properties influence the durability, value, and suitability of each gemstone for different types of jewelry. For example, turquoise, due to its softness and sensitivity, is best suited for pendants and earrings, whereas blue topaz can be used in rings and bracelets due to its high hardness.
Symbolism and Metaphysical Beliefs
Gemstones have long been associated with spiritual and metaphysical properties, and December’s birthstones are no exception. Each stone carries its own set of symbolic meanings and healing properties, rooted in ancient traditions and modern interpretations.
Turquoise – The Stone of Protection and Communication
Turquoise has been revered for thousands of years as a stone of protection, healing, and communication. In ancient Egypt, it was believed to ward off evil spirits and was often used in amulets. Native American tribes, especially the Navajo and Hopi, valued turquoise as a sacred stone that brought good fortune, health, and spiritual connection.
Modern metaphysical practitioners believe that turquoise enhances verbal communication, calms the mind, and promotes emotional balance. It is also associated with friendship and loyalty, making it a popular gift for loved ones.
Tanzanite – The Stone of Transformation and Intuition
Discovered in the 20th century, tanzanite is considered a stone of transformation and spiritual awakening. It is believed to enhance intuition, emotional healing, and self-awareness. Tanzanite is also associated with chakra alignment, particularly the heart and throat chakras, which are linked to love, compassion, and communication.
In ancient traditions, tanzanite was sometimes used in healing rituals and was believed to help individuals navigate major life changes with grace and clarity.
Zircon – The Stone of Wisdom and Prosperity
Zircon has been used in jewelry and spiritual practices for centuries. It is often associated with wisdom, prosperity, and truth. Some cultures believed that zircon could protect against nightmares and bring clarity to the mind.
In modern metaphysical practices, zircon is used to enhance mental focus, stimulate creativity, and promote emotional stability. Its vibrant blue color is also believed to calm the nervous system and reduce stress.
Blue Topaz – The Stone of Calm and Clarity
Blue topaz is associated with calmness, clarity, and emotional healing. It is often used to soothe anxiety, promote inner peace, and encourage rational thinking. Some believe that blue topaz can enhance communication skills and help individuals express themselves more clearly and confidently.
In ancient traditions, blue topaz was thought to attract love and friendship, making it a popular choice for engagement rings and romantic gifts.
Care and Cleaning Tips
Proper care is essential to preserving the beauty and longevity of any gemstone. Given the variability in hardness and sensitivity, the care instructions for each December birthstone differ.
Turquoise
- Avoid exposure to water, heat, and chemicals such as lotions or perfumes.
- Store in a cool, dry place, away from other gemstones to prevent scratches.
- Use a soft cloth for gentle cleaning; avoid using ultrasonic or steam cleaners.
Tanzanite
- Avoid exposure to high heat and direct sunlight for prolonged periods, as it can cause color fading.
- Clean with mild soap and warm water, using a soft brush.
- Avoid harsh chemicals or abrasive cleaners.
Zircon
- Resists heat and light, but can be cleavable, so avoid hard knocks.
- Clean with mild soap and water, using a soft cloth or brush.
- Avoid steam or ultrasonic cleaners, especially for zircon with inclusions.
Blue Topaz
- Highly durable and can be cleaned easily.
- Use mild soap and warm water, a soft brush, or an ultrasonic cleaner.
- Can be exposed to sunlight without fading.
Conclusion
December’s birthstones—turquoise, tanzanite, zircon, and blue topaz—offer a rich tapestry of beauty, history, and meaning. Each gemstone has its own distinctive properties, cultural significance, and metaphysical attributes, making them not only valuable in jewelry but also meaningful in personal and spiritual contexts.
From the protective and communicative qualities of turquoise, to the transformative energy of tanzanite, the wisdom of zircon, and the calming influence of blue topaz, these stones reflect the depth and diversity of December’s symbolism. Whether chosen for their aesthetic appeal, spiritual resonance, or historical significance, these gemstones continue to captivate and inspire across generations.