Individuals born in December are uniquely fortunate, as they are associated with three distinct and captivating gemstones: Turquoise, Tanzanite, and Blue Zircon. This abundance sets December apart from most other months, which typically claim a single birthstone. Each of these gems possesses a unique geological origin, a rich history, and a specific aesthetic that reflects the wintry month of their birth. From the ancient protective talismans of Turquoise to the recent geological discovery of Tanzanite and the fiery brilliance of Blue Zircon, these stones offer a diverse palette of color and meaning. This guide explores the history, properties, sources, and symbolism of each of these December birthstones, providing a detailed resource for gemstone enthusiasts, collectors, and those seeking a meaningful piece of jewelry.
History and Lore of the December Birthstones
The three December birthstones have traveled distinct paths through history, each accumulating a wealth of cultural significance and lore.
Turquoise: As the traditional December gem, Turquoise boasts one of the longest histories of any gemstone. Its use dates back thousands of years, with evidence of its admiration in Ancient Egypt, Persia, and among Indigenous American cultures. For centuries, Turquoise has been regarded as a protective talisman, believed to ward off negative forces and bring good fortune to the wearer. Its distinctive blue-to-green hue and characteristic natural matrix, or webbing, make every piece a unique geological fingerprint. This individuality has contributed to its enduring appeal as a personal amulet and a symbol of friendship and good fortune.
Tanzanite: In stark contrast to Turquoise's ancient lineage, Tanzanite is a remarkably modern addition to the world of gemstones. It was first discovered in the mid-20th century in the Merelani hills of northern Tanzania, near the base of Mount Kilimanjaro. Its discovery is a recent chapter in geological history, and it was quickly recognized for its captivating violet-blue color. Tiffany & Co. named the stone after its country of origin and heavily promoted it, cementing its status as a prized gem. Because of its single-source origin, it is often described as "a million times rarer than diamond." Tanzanite is said to suit the focused and thoughtful personality of the Capricorn, the zodiac sign for the latter half of December.
Blue Zircon: While Zircon is one of the oldest minerals on Earth, dating back billions of years, its use as a prominent gemstone has evolved. The blue variety, in particular, became a celebrated December birthstone. It is known for its exceptional brilliance and fire, often rivaling that of diamonds. Historically, zircon was confused with the synthetic cubic zirconia, but natural zircon is a distinct and valuable gem. Sources indicate that Blue Zircon supports the adventurous and idealistic nature of Sagittarius, the zodiac sign for the first part of December. Its icy, bright appearance makes it a popular choice for those seeking a gem with high brilliance and a clear, wintery aesthetic.
Geological Formation and Sources
Understanding the geological origins of these gems reveals why they are so different in appearance and availability.
Turquoise is a hydrous phosphate of copper and aluminum. It forms in arid regions where acidic, copper-rich groundwater seeps through aluminum-bearing rocks, depositing minerals in nodules and veins. This process results in the porous, opaque structure characteristic of Turquoise. Major sources mentioned in the provided materials include the Southwestern United States (Arizona, New Mexico, Nevada), as well as historic mines in Iran (Persia) and Egypt. The presence of a "matrix"—the host rock embedded within the gem—varies by location and is a key factor in grading and identifying the stone.
Tanzanite is the blue-to-violet variety of the mineral zoisite. Its formation is unique and geologically specific. It is found in only one place on Earth: a small, four-square-kilometer mining area in the Merelani hills of Tanzania. The gem's formation is believed to be linked to a metamorphic event that occurred during the formation of the East African Rift, where heat and pressure chemically altered the host rock, transforming brownish zoisite into the vibrant blue stone we know today. This singular source location contributes to its rarity and value.
Blue Zircon is the gem-quality variety of the mineral zircon (zirconium silicate). It is a common mineral found in many types of rocks but is often altered or metamict (damaged by its own radioactivity). Gem-quality zircon is found in various locations worldwide, including Cambodia, Sri Lanka, Thailand, and Australia. The deep blue color often seen in jewelry is typically the result of heat treatment, which can transform brownish zircon into a stable, vibrant blue. This process enhances the stone's natural brilliance and clarity.
Gemological Properties
Each December birthstone has a unique set of physical and chemical properties that define its durability, appearance, and care requirements. The following table summarizes the key gemological properties based on the information provided.
| Property | Turquoise | Tanzanite | Blue Zircon |
|---|---|---|---|
| Mineral Species | Hydrous phosphate of copper & aluminum | Zoisite | Zircon |
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O | Ca₂Al₃(SiO₄)₃(OH) | ZrSiO₄ |
| Hardness (Mohs) | 5 - 6 | 6.5 - 7 | 6.5 - 7.5 |
| Crystal System | Triclinic | Orthorhombic | Tetragonal |
| Refractive Index | 1.610 - 1.650 | 1.690 - 1.700 | 1.920 - 1.980 |
| Luster | Waxy to subvitreous | Vitreous (Glass-like) | Adamantine (Brilliant) |
| Transparency | Opaque | Transparent to translucent | Transparent |
| Key Feature | Unique matrix patterns | Strong pleochroism (shows different colors from different angles) | High refractive index and fire |
Turquoise
Turquoise is an opaque gem with a hardness of 5 to 6 on the Mohs scale, making it relatively soft and susceptible to scratching and breakage. Its waxy to subvitreous luster gives it a characteristic soft glow rather than a sharp brilliance. The chemical composition results in a porous structure, which is why it is often stabilized or treated to enhance its durability and color. The refractive index ranges from 1.610 to 1.650.
Tanzanite
Tanzanite is a transparent gem with a hardness of 6.5 to 7, making it suitable for most jewelry types, though it requires some care. It has a vitreous luster. A key gemological feature of Tanzanite is its strong pleochroism, meaning it displays different colors—blue, violet, and burgundy—when viewed from different crystal directions. This property is a critical identifier for the stone. Its refractive index is between 1.690 and 1.700.
Blue Zircon
Blue Zircon is a transparent gem known for its exceptional brilliance. With a hardness of 6.5 to 7.5, it is the most durable of the three December stones. Its most notable property is its high adamantine luster and high refractive index (1.920 - 1.980), which gives it significant "fire," or the ability to split light into a spectrum of colors, similar to a diamond. This high brilliance makes it a popular and dazzling choice for jewelry.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, the December birthstones are deeply imbued with symbolism and are believed to possess various metaphysical properties.
Turquoise is widely regarded as a stone of protection, healing, and good fortune. It is often called the "Master Healer" and is believed to absorb negative energy and promote tranquility. Its lore connects it to friendship, wisdom, and spiritual grounding. For those born in December, it is said to provide a shield against harm and attract prosperity.
Tanzanite is associated with transformation, intuition, and spiritual awakening. It is believed to facilitate a higher consciousness and a clearer connection between the mind and heart. As a modern gem, its metaphysical properties are often linked to its rarity and its connection to the majestic landscape of its origin. It is thought to promote calmness and a focused, thoughtful state of mind, aligning well with the Capricorn personality.
Blue Zircon is associated with clarity, purity, and prosperity. It is believed to aid in overcoming obstacles and achieving one's goals. Its bright, clear energy is said to stimulate self-confidence and encourage a positive outlook. For the adventurous Sagittarius, Blue Zircon is thought to enhance their optimistic and idealistic nature, bringing good fortune and peace of mind.
Care and Cleaning
Due to their differing physical properties, each December gemstone requires specific care to maintain its beauty and integrity.
Turquoise: With a hardness of only 5-6 and a porous nature, Turquoise is the most delicate of the three. It is susceptible to damage from heat, chemicals (including perfumes, lotions, and cleaning agents), and even prolonged exposure to sunlight, which can cause fading or discoloration. To clean Turquoise, use only warm water, a mild soap, and a soft cloth. Avoid ultrasonic cleaners and steam cleaners entirely.
Tanzanite: This gem, with a hardness of 6.5-7, is relatively durable but can be prone to chipping if struck against a hard surface. It is also sensitive to rapid temperature changes, which can cause fracturing. The best method for cleaning Tanzanite is with warm, soapy water and a soft brush. As with Turquoise, it is best to avoid ultrasonic and steam cleaners.
Blue Zircon: Although it is the hardest and most brilliant of the group, Blue Zircon can be brittle due to its crystal structure. It is important to protect it from sharp blows that could cause chipping. Cleaning is straightforward: use warm, soapy water and a soft brush. While some Blue Zircon may be treated with heat to achieve its blue color, this treatment is generally stable. However, it is still prudent to avoid harsh chemicals and extreme temperatures.
Conclusion
The December birthstones—Turquoise, Tanzanite, and Blue Zircon—offer a remarkable trio of choices that cater to a wide range of tastes and styles. Turquoise provides a connection to ancient history and the earth with its protective lore and unique matrix patterns. Tanzanite, a product of a unique geological event, offers a modern rarity and a captivating violet-blue hue. Blue Zircon delivers unparalleled brilliance and fire, reminiscent of the clearest winter sky. Together, they represent the diversity and depth of the final month of the year. Whether chosen for their historical significance, symbolic meaning, or sheer gemological beauty, these three stones ensure that anyone born in December has access to a truly special and meaningful gem.