December is unique among the months for its association with not one, but several celebrated birthstones. This abundance offers individuals born in the final month of the year a remarkable spectrum of choice in color, style, and symbolism. The traditional and modern birthstones for December—Turquoise, Tanzanite, Zircon, and Blue Topaz—are all primarily known for their captivating blue hues, ranging from the soft, earthy tones of turquoise to the vivid, shifting blues of tanzanite. This guide delves into the rich history, geological origins, gemological properties, and cultural significance of these four distinct gemstones, providing a comprehensive resource for enthusiasts, collectors, and anyone seeking to understand the gems of December.
History and Lore
The history of December’s birthstones is as diverse as the stones themselves, with roots stretching back millennia. Turquoise, in particular, boasts one of the most ancient lineages of any gemstone. This December birthstone has been cherished for over 6,000 years, with evidence of its use in ancient Egypt, where pharaohs and other rulers adorned themselves with it. Chinese artisans carved turquoise more than 3,000 years ago, and it has held sacred status in many cultures worldwide. Beyond its decorative use, turquoise was historically believed to possess powerful protective and beneficial properties. It was thought to guarantee health and good fortune and was believed to protect the wearer from falls, particularly from horses. From the 13th century onward, it was held that a turquoise would break into several pieces at the approach of disaster, serving as a warning to its wearer. Hindu mystics believed that seeing a turquoise after beholding the new moon would ensure fantastic wealth. For Native Americans, particularly the Apache, turquoise held deep spiritual significance; they believed the stone could be found by following a rainbow to its end. The stone’s name is derived from the French pierre turquoise, meaning "Turkish stone," reflecting the historical trade route through which it reached Europe from Persia (modern-day Iran), a primary source for high-quality turquoise.
Tanzanite’s history is considerably more modern. Discovered in the late 1960s in a single small area in Tanzania, it is a relative newcomer to the gemstone world. Its rapid ascent to popularity is a testament to its extraordinary color. Initially mistaken for other blue minerals, its unique violet-blue hue, which can shift from royal blue to deep violet depending on the light, was quickly recognized. The gemstone was later named by Tiffany & Co. after its country of origin, with a marketing campaign that helped establish it as a prized gem. While it lacks the ancient lore of turquoise, modern sources associate tanzanite with themes of transformation and new beginnings, reflecting its recent geological formation and discovery.
Zircon is one of the oldest minerals on Earth, with some crystals dating back billions of years. However, its use as a gemstone and its association with December are part of a longer historical journey. For centuries, blue zircon was particularly popular in Europe during the Victorian era. Its name is often confused with the synthetic cubic zirconia, but natural zircon is a distinct and ancient mineral. In traditional lists, zircon is recognized as a December birthstone alongside turquoise. Modern sources attribute to zircon the symbolism of clarity, wisdom, and a sense of balance.
Blue Topaz, while not traditionally listed in the earliest birthstone lists, has gained significant popularity in modern times and is frequently considered a mainstream December birthstone. Its history is intertwined with the mineral topaz, which has been known since antiquity. The name "Topaz" is believed to originate from the Greek word "Topazios," the ancient name for an island in the Red Sea. However, it was later determined that the stones from this island were actually peridot, not topaz. Despite this historical confusion, blue topaz has carved out its own identity. Its vivid sky-blue to aqua tones, achieved largely through modern treatment processes, have made it a beloved choice for contemporary jewelry.
Geological Formation and Sources
Understanding the formation and sources of these gemstones provides insight into their rarity and unique characteristics.
Turquoise is a secondary mineral, meaning it forms in the near-surface environment where pre-existing minerals are altered by water. It is a phosphate of copper and aluminum that forms in arid regions where acidic, copper-rich water seeps through aluminum-bearing rocks. The specific conditions of its formation result in the stone’s characteristic porous nature and often the presence of matrix—the host rock remnants that create the distinctive webbed patterns in many turquoise specimens. Major sources of turquoise include Iran (historically the source of the finest "Persian turquoise"), the United States (particularly Arizona, New Mexico, and Nevada, which produce a wide variety of colors and matrix patterns), Tibet, and India. The geographic origin can significantly influence the stone’s color and matrix characteristics.
Tanzanite is found in only one location on Earth: the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. This extremely limited geographic source contributes to its rarity and value. The gemstone forms from the metamorphism of limestone, a process that subjected the rock to high heat and pressure, causing the mineral zoisite to develop its signature blue and violet colors. The geological conditions required for tanzanite’s formation are exceptionally rare, making its single-source origin a key factor in its market positioning.
Zircon is a mineral that forms in igneous and metamorphic rocks. It is a zirconium silicate (ZrSiO₄) that is highly resistant to weathering, which is why it is often found in sedimentary deposits as well. The blue color in zircon is typically achieved through heat treatment of brownish zircon crystals. Major sources for gem-quality zircon include Sri Lanka, Cambodia, and Australia. Its durability and high refractive index make it a valuable gemstone, though it can be brittle.
Blue Topaz is a silicate mineral that forms in igneous rocks, particularly in pegmatites and hydrothermal veins. Natural blue topaz is relatively rare; most of the vibrant blue topaz on the market today starts as colorless or pale blue topaz that is irradiated and then heated to achieve its deep blue hue. This treatment process is stable and widely accepted in the gem trade. Topaz is mined in various locations worldwide, including Brazil, Nigeria, Sri Lanka, and the United States. Its hardness and clarity make it suitable for a wide range of jewelry applications.
Gemological Properties
The gemological properties of these stones dictate their durability, care requirements, and suitability for different types of jewelry. The following table summarizes key properties based on the provided sources.
| Property | Tanzanite | Turquoise | Zircon | Blue Topaz |
|---|---|---|---|---|
| Mineral Group | Zoisite (variety) | Phosphate | Zirconium Silicate | Silicate |
| Chemical Formula | Ca₂(Al,OH)₂Si₃O₁₀ | CuAl₆(PO₄)₄(OH)₈·4H₂O | ZrSiO₄ | Al₂SiO₄(F,OH)₂ |
| Mohs Hardness | 6 to 7 | 5 to 6 | 6.5 to 7.5 | 8 |
| Crystal System | Orthorhombic | Triclinic | Tetragonal | Orthorhombic |
| Refractive Index | 1.691–1.700 | 1.610–1.650 | 1.92–2.01 | 1.609–1.627 |
| Specific Gravity | 3.35 | 2.60–2.90 | 4.60–4.70 | 3.53 |
| Natural Color | Blue to violet | Sky blue to greenish | Blue (from treatment) | Pale blue to dark blue |
| Transparency | Transparent to translucent | Semi-translucent to opaque | Transparent | Transparent |
| Common Treatments | Heat treatment | Stabilization (impregnation) | Heat treatment | Irradiation and heat |
| Care & Sensitivity | Prone to chipping; gentle cleaning only | Sensitive to chemicals, heat, and moisture; avoid ultrasonic cleaners | Brittle; avoid steam and ultrasonic cleaners | Sensitive to sharp impacts; mild care |
Hardness and Durability: Blue Topaz, with a Mohs hardness of 8, is the most durable of the group, making it suitable for daily wear in rings. Zircon (6.5–7.5) and Tanzanite (6–7) are moderately durable but can be brittle; Zircon is prone to chipping at its edges, and Tanzanite is also susceptible to chipping. Turquoise, with a hardness of 5–6, is the softest and most delicate, requiring careful handling and protection from scratches and blows.
Color and Treatment: All four stones are available in shades of blue, but their origins and treatments differ. Turquoise’s color is natural, ranging from sky blue to greenish hues, often with matrix. Tanzanite’s signature violet-blue color is natural but is almost always heat-treated to enhance its blue tones. Zircon’s blue color is typically the result of heat treatment applied to brownish crystals. Blue Topaz’s vibrant blue is almost always the result of irradiation and heat treatment applied to colorless or pale blue topaz.
Clarity and Inclusions: Turquoise is typically opaque to semi-translucent and often contains matrix, which is considered part of its character. The other three stones are usually transparent to translucent. Zircon can have inclusions, and its high refractive index gives it a brilliant sparkle. Tanzanite and Blue Topaz are valued for their clarity and brilliance.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, these gemstones are rich with symbolic meaning and metaphysical beliefs, many of which have been passed down through centuries.
Turquoise is universally regarded as a stone of protection, healing, and good fortune. It is believed to absorb negative energy and protect the wearer from harm. Historically, it was thought to ensure health and was often used as a talisman against falls and accidents. It is also associated with friendship, truth, and calmness, making it a meaningful gift for loved ones.
Tanzanite, a modern gem, carries symbolism aligned with its unique properties. It is associated with transformation, intuition, and new beginnings. Its ability to show different colors under different lights is often linked to the idea of seeing situations from multiple perspectives and embracing change.
Zircon is traditionally associated with clarity, wisdom, and balance. It is believed to enhance spiritual growth and help the wearer achieve a sense of stability and mental clarity. Its sparkling fire is thought to stimulate joy and self-confidence.
Blue Topaz is associated with clear communication, calm, and serenity. Its soothing blue hues are believed to promote peace and tranquility. It is often linked to the throat chakra in metaphysical traditions, supporting honest and clear expression.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, with requirements varying significantly based on their physical properties.
Turquoise: As a porous and soft stone, turquoise is highly sensitive to chemicals, heat, and moisture. It should never be cleaned with ultrasonic cleaners, steam, or harsh chemicals. The best method is gentle wiping with a soft, damp cloth. Some turquoise is stabilized (impregnated with a clear resin) to improve durability and color, but it still requires careful handling. Store it separately to avoid scratches from harder gems.
Tanzanite: With a hardness of 6 to 7, tanzanite is moderately durable but prone to chipping due to its cleavage. It should be protected from sharp blows and extreme temperature changes. Clean it only with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as the vibrations and heat can cause damage.
Zircon: Although relatively hard, zircon is brittle and can be scratched or chipped. It is sensitive to heat and pressure. Cleaning should be done with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are not recommended, as they can cause fractures in the stone.
Blue Topaz: As the hardest of the group, blue topaz is relatively easy to care for. It can be cleaned with warm, soapy water and a soft brush. However, it is still sensitive to sharp impacts and should be protected from hard knocks. Ultrasonic cleaners are generally safe for clean, fracture-free stones, but steam cleaning is not recommended due to the potential for thermal shock.
Conclusion
The December birthstones—Turquoise, Tanzanite, Zircon, and Blue Topaz—offer a remarkable array of choices, each with its own distinct character, history, and properties. From the ancient, protective talisman of turquoise to the modern, transformative allure of tanzanite; from the fiery brilliance of zircon to the serene, icy sparkle of blue topaz, these gemstones provide a meaningful connection to the natural world and to cultural traditions. Their varying levels of durability, from the delicate turquoise to the sturdy blue topaz, guide their use in jewelry, influencing both design and care. Understanding their unique gemological properties, historical significance, and symbolic meanings allows individuals to make informed choices, selecting a stone that not only captures their aesthetic preference but also resonates with their personal story. For those born in December, the abundance of options is a celebration, ensuring a perfect gemstone for every style and occasion.
Sources
- Gabriel & Co. (n.d.). What is December's Birthstone? Retrieved from https://www.gabrielny.com/blog/what-is-decembers-birthstone/
- MyCrystals.com (n.d.). December Birthstone Color: Topaz, Turquoise, Tanzanite, Zircon. Retrieved from https://www.mycrystals.com/guide/december-birthstone-color-topaz-turquoise-tanzanite-zircon
- Bluestone Blog (n.d.). December Birthstone Guide: Meaning, Colours, Zodiac Signs & Alternatives. Retrieved from https://blog.bluestone.com/december-birthstone-guide-meaning-colours-zodiac-signs-alternatives/
- GIA (n.d.). December Birthstones. Retrieved from https://www.gia.edu/birthstones/december-birthstones
- Pattiring (n.d.). Complete List of December Birthstones. Retrieved from https://pattiring.com/blog/gemstone-jewelry/complete-list-of-december-birthstones/