For individuals born on December 16, the birthstone selection is notably diverse, encompassing three distinct gemstones: Tanzanite, Turquoise, and Zircon. This convergence is unique, as December is one of the few months with multiple official birthstones, offering a spectrum of colors, histories, and symbolic meanings. These stones—though varied in their gemological properties—are united by their association with themes of success, protection, and inner strength, making them deeply meaningful for those born on this day. This article explores the rich lore, scientific properties, and cultural significance of these gemstones, drawing from authoritative sources to provide insights into their origins, uses, and metaphysical beliefs. We will examine the broader context of December’s birthstones, including their traditional and modern designations, and why December is uniquely represented by multiple gemstones.
Historical Context and the Modern Birthstone List
The tradition of birthstones is ancient, with roots tracing back to the biblical description of Aaron’s breastplate in the Book of Exodus, which featured twelve gemstones representing the twelve tribes of Israel. Over centuries, this list evolved, with variations appearing in different cultures and historical periods. The modern birthstone list, as recognized by the American Gem Society and the Jewelers of America, solidified in 1912 and has been updated periodically to include new discoveries and market trends.
December stands out in this modern list because it is associated with three gemstones: Turquoise, Zircon, and Tanzanite. This multiplicity offers a variety of colors and styles, catering to personal preference. Turquoise, with its ancient history, was the traditional birthstone for December. In the early 20th century, Zircon was added as a modern alternative, prized for its brilliance and clarity. More recently, in 2002, the American Gem Trade Association (AGTA) added Tanzanite as an official birthstone for December, recognizing its rising popularity and unique appeal. This layered history means that an individual born on December 16 can choose a stone that resonates with their personal style, from the sky-blue hues of Turquoise to the brilliant blue of Zircon or the violet-blue of Tanzanite.
Tanzanite: The Modern Marvel of Tanzania
Tanzanite is a relatively modern addition to the gemstone world, discovered in the 1960s. It is known for its deep blue to violet hues and its exclusive origin in Tanzania, near Mount Kilimanjaro. This gemstone is a variety of the mineral zoisite and is celebrated for its vivid, pleochroic color—showing different shades of blue and violet depending on the viewing angle.
Historical Discovery and Origin
Tanzanite’s story is one of recent discovery and rapid rise to prominence. Unlike gemstones with millennia of history, Tanzanite’s journey began in the mid-20th century. It was first identified in the Merelani Hills of northern Tanzania, a small mining area near the base of Mount Kilimanjaro. Its discovery is often attributed to a Maasai herdsman in 1967, who found translucent blue crystals in the region. The gemstone was soon recognized by Tiffany & Co., which launched a marketing campaign in 1968 that helped catapult Tanzanite to international fame. Due to its limited geographical source, Tanzanite is considered one of the rarest gemstones on Earth, with all commercial production coming from a single area in Tanzania.
Gemological Properties
Tanzanite is a member of the zoisite family, with a chemical composition of Ca₂Al₃(SiO₄)₃(OH). It has a hardness of 6.5 to 7 on the Mohs scale, making it relatively durable but softer than many other gemstones. Its refractive index ranges from 1.690 to 1.700, and it exhibits strong trichroism, displaying blue, violet, and red-violet colors from different crystallographic directions. The most valued color is a rich, saturated violet-blue, often referred to as "cornflower blue." Most Tanzanite in the market is heat-treated to enhance its blue color, a standard and accepted practice that removes brownish overtones. Clarity is generally good, with inclusions being relatively common but often not affecting the stone's transparency.
Symbolism and Metaphysical Beliefs
Tanzanite is imbued with a myriad of meanings and symbolisms, both traditional and metaphysical. It is often associated with spiritual enlightenment and awakening. Believed to open the third eye and enhance intuition, this birthstone is thought to guide individuals on a journey of self-discovery and heightened awareness. The vibrant blue hues of Tanzanite are also believed to stimulate clear communication and self-expression, aiding in articulating thoughts and emotions and fostering effective communication in personal and professional relationships. Furthermore, Tanzanite is revered for its ability to facilitate transformation and change, encouraging personal growth and helping individuals navigate life’s transitions with grace and resilience. In metaphysical beliefs, it is considered a protective stone that dispels negative energies and promotes physical and emotional well-being.
Turquoise: The Ancient Stone of Protection
Turquoise is one of the oldest known gemstones, with a history that spans thousands of years. Its name derives from the French "pierre turquoise," meaning "Turkish stone," as it was brought to Europe from Turkey via the Silk Road. It is an opaque mineral, a hydrous phosphate of copper and aluminum, with a hardness of 5 to 6 on the Mohs scale, making it relatively soft and porous.
Historical Significance and Sources
Turquoise has been prized by ancient civilizations across the globe, including the Egyptians, Persians, Native Americans, and Chinese. It was used for jewelry, amulets, and ceremonial objects, often symbolizing wealth, status, and spiritual protection. The earliest known turquoise mining dates back to ancient Egypt, around 6000 BCE, where it was mined in the Sinai Peninsula. In North America, the Anasazi and later the Navajo, Zuni, and Hopi tribes have a long tradition of turquoise use, with mines in states like Arizona, New Mexico, and Nevada producing some of the finest specimens. The stone’s color ranges from sky blue to greenish hues, often influenced by the presence of iron or zinc in its composition.
Gemological Properties
Turquoise is a phosphate mineral with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. Its color is primarily due to copper, with iron and zinc substituting for copper leading to greenish tones. It has a hardness of 5 to 6 on the Mohs scale and a specific gravity of 2.6 to 2.9. Turquoise is typically cut en cabochon to highlight its color and often exhibits a waxy to vitreous luster. A unique characteristic of high-quality turquoise is the presence of a matrix—the host rock that remains embedded in the stone, creating intricate spiderweb or patchy patterns. These matrix patterns, particularly from specific mines like those in Arizona or Iran, can significantly affect the stone's value.
Symbolism and Metaphysical Beliefs
Turquoise is deeply symbolic, often associated with protection, good fortune, and healing. Historically, it was believed to ward off evil and protect the wearer from harm. For many Native American cultures, turquoise represents a connection to the sky and water, symbolizing life and fertility. Metaphysically, turquoise is thought to promote calm, balance, and emotional stability. It is often used as a talisman for travelers and those seeking spiritual grounding. The stone’s color variations—from sky blue to green—are also linked to different aspects of well-being, with blue representing tranquility and green symbolizing growth and renewal.
Zircon: The Brilliant and Misunderstood Gem
Zircon is a naturally occurring mineral that should not be confused with the synthetic cubic zirconia. It is one of the oldest minerals on Earth, with zircon crystals found in ancient rocks dating back billions of years. Zircon occurs in a variety of colors, but the most prized for jewelry is the bright, clear blue variety, which is often heat-treated to enhance its color.
Historical Context and Sources
Zircon has a long history of use in jewelry, though it has often been overshadowed by other gemstones. In the Middle Ages, it was believed to promote sleep, ward off evil spirits, and bring prosperity. The blue variety of zircon became particularly popular in the Victorian era for its brilliance and affordability. Zircon is mined in several countries, including Sri Lanka, Thailand, Australia, and the United States. The blue color is typically achieved through heat treatment of brown or reddish-brown zircon, a process that is stable and widely accepted in the gem trade.
Gemological Properties
Zircon is a zirconium silicate mineral with the chemical formula ZrSiO₄. It has a high refractive index (1.92–2.01) and strong dispersion, giving it exceptional brilliance and fire, often compared to diamond. Zircon is relatively hard, with a Mohs hardness of 7.5, making it durable for jewelry, though it can be brittle due to its cleavage. Its specific gravity ranges from 4.6 to 4.7, and it exhibits high birefringence, which can sometimes cause doubling of facets in cut stones. The blue zircon commonly seen in jewelry is usually heat-treated to achieve a vibrant blue color, though natural blue zircon is rare and valuable.
Symbolism and Metaphysical Beliefs
Zircon is associated with clarity, wisdom, and a sense of balance. It is believed to enhance mental clarity, promote spiritual growth, and bring prosperity to the wearer. In some traditions, zircon is thought to protect against negative energies and to help in making wise decisions. The stone’s brilliance and clarity are often linked to its ability to reflect truth and insight. For those born on December 16, wearing zircon is said to foster confidence and inner strength, aligning with the themes of success and protection associated with December’s birthstones.
Comparative Gemological Properties
To better understand the differences and similarities among these three gemstones, the following table summarizes their key gemological properties based on the provided sources. Note that specific values like refractive index and specific gravity are not detailed in all sources, so the table includes only the data explicitly mentioned or clearly inferable from the text.
| Property | Tanzanite | Turquoise | Zircon |
|---|---|---|---|
| Chemical Composition | Ca₂Al₃(SiO₄)₃(OH) | CuAl₆(PO₄)₄(OH)₈·4H₂O | ZrSiO₄ |
| Hardness (Mohs) | 6.5 - 7 | 5 - 6 | 7.5 |
| Color | Deep blue to violet, pleochroic | Sky blue to greenish hues | Bright, clear blue (often heat-treated) |
| Transparency | Transparent to translucent | Opaque | Transparent |
| Origin | Exclusively Tanzania (Merelani Hills) | Various, including USA (Arizona, New Mexico), Iran, Egypt | Sri Lanka, Thailand, Australia, USA |
| Key Treatments | Heat treatment to enhance blue color | Stabilization (resin/epoxy) common | Heat treatment for blue color |
| Symbolic Meaning | Spiritual enlightenment, communication, transformation | Protection, good fortune, healing | Clarity, wisdom, balance |
Care and Cleaning for December Birthstones
Proper care is essential to maintain the beauty and longevity of these gemstones, given their varying levels of durability. The following guidelines are based on their gemological properties and general industry knowledge.
Tanzanite
With a hardness of 6.5 to 7, Tanzanite is moderately durable but can be susceptible to scratching and chipping. It is also sensitive to heat and sudden temperature changes, which can cause cracking. To clean Tanzanite jewelry, use warm, soapy water and a soft brush, then rinse thoroughly. Avoid ultrasonic cleaners, steam cleaning, and harsh chemicals. Store Tanzanite separately from harder gemstones to prevent scratches.
Turquoise
Turquoise is the softest of the three, with a hardness of 5 to 6, and is porous, making it vulnerable to chemicals, perfumes, and oils. It is often stabilized with resin or epoxy to enhance its durability. To clean turquoise, use a damp, soft cloth and mild soap, then dry immediately. Avoid submersion in water, ultrasonic cleaners, and exposure to cosmetics or lotions. Store it in a soft pouch to protect it from scratches.
Zircon
Zircon has a good hardness of 7.5 but can be brittle due to cleavage. It is generally safe to clean with warm, soapy water and a soft brush. Avoid sudden impacts and extreme temperature changes, as zircon can fracture. Ultrasonic cleaning is generally not recommended due to the risk of fracturing, especially if the stone has inclusions or is set in delicate jewelry. Store zircon separately to avoid scratching other gems.
Conclusion
The birthstones for December 16—Tanzanite, Turquoise, and Zircon—offer a remarkable diversity in color, history, and symbolism. Tanzanite, a modern marvel from Tanzania, embodies spiritual enlightenment and transformation. Turquoise, an ancient stone of protection, carries the legacy of cultures worldwide with its soothing blue-green hues. Zircon, a brilliant and often misunderstood gem, represents clarity and wisdom. Together, they provide a rich palette for those born on this day, allowing for personal expression and connection to timeless themes of success, protection, and inner strength. Whether chosen for their beauty, historical significance, or metaphysical properties, these gemstones remain enduring symbols of December’s unique and multifaceted character.