Introduction
December is uniquely adorned with a trio of gemstones—tanzanite, zircon, and turquoise—each embodying the cool, wintry palette of the season. These birthstones are celebrated for their distinct colors, historical narratives, and gemological properties. While turquoise has been cherished for millennia, tanzanite is a modern discovery, and zircon boasts a brilliance that has long been confused with diamond. This article provides an in-depth exploration of these three remarkable gems, delving into their geological origins, gemological characteristics, historical lore, and practical care, offering a definitive resource for enthusiasts, collectors, and those born in the final month of the year.
History and Lore
Tanzanite: The Modern Marvel
Tanzanite’s history is remarkably brief, making it one of the youngest gemstones in the jewelry market. It was first discovered as a mineral in 1962 by Manuel de Sousa, who initially identified it as blue-violet zoisite. The stone’s dramatic rise to prominence began in 1968, when the renowned jewelry house Tiffany & Co. recognized its potential and launched a significant promotional campaign. Tiffany & Co. bestowed the name "tanzanite," derived from its exclusive origin in Tanzania, and successfully introduced it to a global audience. Its rapid acceptance was bolstered by its association with the 24th wedding anniversary, a tribute to its enduring beauty. Beyond its commercial success, tanzanite is often linked to themes of transformation and new beginnings, reflecting its journey from a lesser-known mineral to a celebrated birthstone.
Zircon: The Ancient Diamond Imitator
Zircon’s etymology is a subject of scholarly debate, with potential roots in the Arabic word zarkun (meaning "cinnabar" or "vermilion") or the Persian word zargun ("gold colored"). This ambiguity is fitting for a gemstone with a broad color spectrum, ranging from red and orange to yellow, brown, green, and blue. For centuries, colorless zircon has been prized for its exceptional brilliance and fire, often leading to confusion with diamond. This historical misidentification is one of the gemstone’s most notable features.
During the Middle Ages, zircon was believed to possess protective qualities, thought to induce deep sleep and ward off evil spirits. In Hindu tradition, zircon is one of the nine gems, or navaratna, where it alternates with hessonite garnet. When worn together, these nine gems are said to offer protection and confer wealth, wisdom, and good health. The Victorian era saw a particular fondness for blue zircon, which became a popular choice in jewelry of that period.
Turquoise: The Timeless Talisman
Turquoise boasts a history that spans millennia and traverses cultures. Evidence of its use dates back to ancient civilizations, where it was revered by royalty, most famously exemplified by the treasures of King Tutankhamun. This ancient mineral was consistently attributed with protective powers, believed to safeguard the wearer from physical harm, such as falls, and from negative energy. Its symbolism has evolved but remains potent; today, turquoise is widely associated with wisdom, tranquility, and friendship. Its enduring appeal as a talisman and a symbol of good fortune has cemented its status as a classic birthstone.
Geological Formation and Sources
Tanzanite: A Singular Origin
Tanzanite’s geological story is as unique as its color. It is a variety of the mineral zoisite and is found exclusively in the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. The formation of tanzanite is linked to a specific geological event: the first eruption of Mount Kilimanjaro, which subjected the parent rock to intense heat and pressure, creating the conditions necessary for this vibrant blue-violet gem to form. This extreme rarity—being confined to a single, small mining area—is a primary factor in its value and desirability.
Zircon: A Widespread Mineral
Unlike tanzanite, zircon is a widespread mineral found in many parts of the world. It forms in a variety of igneous and metamorphic rocks and can be found in placer deposits. While the sources do not list specific countries for zircon mining, its global distribution is implied by its use in various cultures and historical periods, from Hindu traditions to Victorian England.
Turquoise: The Arid Environment Gem
Turquoise is a secondary mineral that forms in arid regions where copper-rich groundwater percolates through pre-existing rock. Specific weather conditions are necessary for its formation, leading to its occurrence in areas like the southwestern United States, Iran, Egypt, China, Mexico, and parts of Central Asia and Africa. Its formation often results in a distinctive matrix—a web-like pattern of host rock (often iron or sandstone) embedded within the turquoise, which contributes to its unique, often spiderweb-like appearance.
Gemological Properties
Understanding the physical characteristics of these gems is crucial for identification, valuation, and care. The following table summarizes key properties based on the provided sources.
| Gemstone | Chemical Composition | Hardness (Mohs Scale) | Key Visual Characteristics | Notable Features |
|---|---|---|---|---|
| Tanzanite | Calcium Aluminum Silicate Hydroxide (Zoisite variety) | Not specified in sources | Deep blue and violet hues; exhibits pleochroism (color shift). | Exclusive to Tanzania; heat treatment is standard to enhance color. |
| Zircon | Zirconium Silicate (ZrSiO₄) | Not specified in sources | Broad color palette; colorless variety known for exceptional brilliance and "fire." | Historically confused with diamond; a key component in the Hindu navaratna. |
| Turquoise | Hydrated Copper Aluminum Phosphate | 5-6 on the Mohs Scale | Ranges from soft sky blue to greenish hues; often features a matrix (spiderweb pattern). | Relatively soft and delicate; primarily mined in arid, copper-rich regions. |
Color and Clarity
Tanzanite is prized for its rich, violet-blue color, which exhibits pleochroism—showing different shades of blue and violet when viewed from different angles. The sources indicate that the color is typically enhanced through heat treatment, a permanent process that does not affect durability.
Zircon offers a remarkable spectrum of colors. While blue zircon is popular for December, the gem is found in many hues. Its colorless form is especially valued for its diamond-like sparkle, characterized by flashes of multicolored light known as fire.
Turquoise is most famous for its blue to green shades, determined by the amount of copper (blue) or iron (green) present during formation. Its clarity is often impacted by its matrix, which is not considered a flaw but rather a characteristic feature of the stone.
Hardness and Durability
Turquoise is the softest of the three, with a hardness of 5-6 on the Mohs scale, making it susceptible to scratches and requiring careful handling. While the sources do not specify the hardness of tanzanite and zircon, they provide clear care instructions that imply relative fragility. Tanzanite is not recommended for daily wear in rings due to its potential for cleavage, and zircon, while harder than turquoise, is not as tough as diamond and can be chipped by sharp impacts.
Symbolism and Metaphysical Beliefs
Each December birthstone carries a legacy of symbolic meaning, often rooted in historical lore and modern metaphysical interpretations.
Tanzanite is strongly associated with transformation, growth, and new beginnings. Its vibrant, shifting hues are seen as a reflection of stepping into new chapters of life with clarity and curiosity. Some modern sources also attribute healing properties to tanzanite, suggesting it can aid in body detoxification, enhance vitality, and promote a sense of calm for both body and soul.
Zircon is linked to mental clarity, focus, and a sense of balance. Its historical use in the Hindu navaratna underscores its role as a stone of protection and good fortune. The Victorian association with blue zircon adds a layer of historical elegance to its symbolism.
Turquoise is a quintessential talisman. It is viewed as a steadying force, offering protection, grounding, and tranquility. In chaotic times, many turn to turquoise for a sense of calm and wisdom. Its symbolism of friendship and good health has made it a popular gift for centuries.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of these gemstones, with care requirements largely dictated by their physical properties.
Tanzanite requires gentle handling. It is best set in protective jewelry such as earrings or pendants. While it can be used in rings with a secure mounting, it is not recommended for daily wear due to its cleavage. For cleaning, warm, soapy water is the safest method. The sources explicitly warn that ultrasonic and steam cleaners should never be used for tanzanite, as they can cause damage.
Zircon is more durable than tanzanite or turquoise but still demands respect. While its specific hardness is not listed, the general advice for zircon jewelry is to avoid sharp knocks, which can chip the stone along its natural cleavage planes. Cleaning should be done with a soft brush and mild soap and water, avoiding harsh chemicals.
Turquoise, with its low hardness of 5-6, is the most delicate of the three. It should be protected from blows, chemicals (including perfumes and lotions), and prolonged exposure to water or sunlight, which can cause fading or discoloration. Cleaning should be done with a soft, dry cloth. The matrix in turquoise can absorb oils and chemicals, so it is best to apply cosmetics and perfumes before putting on turquoise jewelry.
Conclusion
Tanzanite, zircon, and turquoise offer a diverse and captivating trio for December-born individuals. From the ancient, protective talisman of turquoise to the historically brilliant zircon and the modern, transformative tanzanite, each gemstone provides a unique narrative. Their distinct colors—ranging from soft sky blue to deep violet—perfectly mirror the cool, serene palette of winter. Understanding their histories, geological origins, gemological properties, and care requirements allows for a deeper appreciation of these remarkable birthstones, ensuring they can be cherished for generations to come.