In the world of gemstones, few months are as visually diverse as December. Its official birthstones—tanzanite, turquoise, and zircon—offer a breathtaking spectrum of color, from the vivid blues of tanzanite and turquoise to the fiery brilliance of zircon. These gems are not only celebrated for their beauty but also for their unique geological origins and cultural significance. Modern jewelry design has embraced these stones, particularly through the medium of personalized gold birthstone necklaces, allowing wearers to carry a piece of this December legacy in a deeply personal way. This article explores the distinct characteristics of each December birthstone, their journey from mine to market, and how they are artfully incorporated into contemporary fine jewelry, focusing on the craftsmanship and customization options available in gold-filled and gold vermeil necklaces.
The tradition of birthstones is a long-standing one, with roots in ancient beliefs and evolving through historical trade and cultural exchange. For December, the assigned stones have shifted over time, but the modern trio represents a balance of rarity, tradition, and brilliance. Tanzanite, a relative newcomer, has rapidly ascended to prominence due to its singular geographic source and captivating color. Turquoise carries the weight of millennia of human history, adorning everything from Egyptian pharaohs to Native American artisans. Zircon, one of the oldest minerals on Earth, offers a diamond-like sparkle that has been prized since antiquity. Together, they provide a rich tapestry for gemologists and jewelry enthusiasts alike.
This article will delve into the geological formation and sources of these gems, detail their specific gemological properties, and explore the symbolism and metaphysical beliefs associated with them. Furthermore, it will examine the practical aspects of caring for these stones and highlight the modern trend of customizing gold jewelry with birthstones, a practice that merges ancient gemology with personal narrative. By understanding the science and story behind each gem, one can appreciate the profound connection between the earth's creations and the art of jewelry making.
December's Birthstone Trio: History and Lore
The concept of a single birthstone per month is a relatively modern convention, largely solidified in the early 20th century. Historically, the association was with specific gems listed in religious texts, such as the breastplate of the High Priest of ancient Israel, which featured twelve stones. For December, the stones have varied, but the current trio—tanzanite, turquoise, and zircon—each has a distinct and storied past.
Turquoise is arguably the most ancient of the December stones. Its use dates back over 5,000 years, with evidence found in ancient Egyptian tombs, including that of Tutankhamun, where a turquoise-inlaid pectoral was discovered. The stone’s name derives from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe from Persia via Turkish traders. In many cultures, turquoise was revered as a protective talisman. Ancient Persians believed it warded off the "evil eye" and symbolized purity. Native American tribes, particularly the Navajo, Zuni, and Pueblo, have a profound connection to turquoise, using it in intricate silverwork for both ceremonial and decorative purposes. For these cultures, the stone represents the sky and water, embodying life, health, and protection. Its lore is deeply embedded in the history of the American Southwest, where it is still mined and revered.
Zircon holds the distinction of being one of the oldest minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. Its name may be derived from the Persian zargun, meaning "gold-colored," though zircon occurs in a variety of hues. For centuries, zircon was confused with the more expensive gemstone, cubic zirconia, and even diamond, due to its high refractive index and brilliance. In the Middle Ages, zircon was believed to promote rest, ward off evil spirits, and bring prosperity and honor to its wearer. It was often placed on armor or used in royal regalia. Today, the blue variety of zircon is the most popular for December, prized for its vivid color and exceptional sparkle.
Tanzanite is the newest addition to the birthstone family. It was first discovered in the Merelani Hills of Tanzania in 1967. Its rapid rise to prominence is a testament to its stunning beauty and unique origin. Initially mistaken for sapphire, it was later identified as a variety of the mineral zoisite. The stone’s vibrant blue-to-violet color is the result of heat treatment, which transforms naturally occurring brownish crystals into their prized blue form. Tiffany & Co. introduced tanzanite to the world in 1968, marketing it as a "generational gemstone" due to its single-source rarity. While it lacks the ancient lore of turquoise or zircon, tanzanite has quickly developed its own mythology, often associated with a sense of new beginnings and the unique connection between the earth and the cosmos.
The modern designation of tanzanite, turquoise, and zircon as December's birthstones was formalized by the American Gem Trade Association (AGTA) and the Jewelers of America (JA) in the 2010s, providing a diverse and visually striking set of options for those born in the last month of the year.
Geological Formation and Sources
The origins of these gems are as varied as their colors, spanning different continents, geological processes, and mining histories.
Turquoise is a secondary mineral that forms in arid regions where water percolates through rocks containing aluminum and copper. The process begins when acidic water, enriched with copper, reacts with aluminous minerals like feldspar. Over millions of years, the turquoise nodules fill veins and cavities in the host rock. The most famous turquoise sources are in the United States, particularly in Arizona (e.g., Sleeping Beauty, Kingman), Nevada (e.g., Royston, Lander Blue), and New Mexico. The stone is also mined in Iran (historically the source of "Persian turquoise"), China, and Mexico. The color of turquoise is influenced by the specific metal content: copper creates blue tones, while iron produces greenish hues. The presence of the host rock (matrix) can create unique patterns, such as the "spiderweb" matrix found in some Nevada stones.
Zircon is a mineral that forms in igneous and metamorphic rocks. It is a zirconium silicate (ZrSiO₄) that crystallizes from magma. Because it is highly resistant to weathering, zircon crystals can survive for billions of years, making them valuable for radiometric dating of the Earth's crust. Significant sources of gem-quality zircon include Cambodia, Sri Lanka, Myanmar, Australia, and Vietnam. The blue variety, which is most associated with December, is typically heat-treated to enhance or change its color. Natural blue zircon is rare. Australian zircon, from the same deposits that yield the world's oldest minerals, often exhibits a rich yellow-brown color that can be transformed into a brilliant blue through careful heating.
Tanzanite is found exclusively in a small, four-square-kilometer area in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This singular source makes it at least a thousand times rarer than diamond. The gem forms through a complex geological process involving the metamorphism of minerals in the presence of hydrothermal fluids. The original brownish crystals of zoisite are heated to temperatures of around 370–450°C to produce the desirable blue-to-violet color. This heating process is standard practice in the industry and is considered permanent. Due to its limited geographic origin, tanzanite is often referred to as "a gem of a lifetime," with experts predicting that the known deposits may be exhausted within a few decades.
Gemological Properties
Understanding the physical and chemical properties of these gems is crucial for gemologists, jewelers, and consumers. Each stone has a unique profile that influences its durability, appearance, and value.
| Gemstone | Chemical Composition | Hardness (Mohs Scale) | Crystal System | Refractive Index | Specific Gravity | Notable Characteristics |
|---|---|---|---|---|---|---|
| Turquoise | Hydrated copper aluminum phosphate | 5–6 | Triclinic | 1.61–1.65 | 2.6–2.9 | Porous, often stabilized or dyed; color can fade with prolonged UV exposure. |
| Zircon | Zirconium silicate (ZrSiO₄) | 6.5–7.5 | Tetragonal | 1.92–2.01 | 4.6–4.7 | High refractive index and strong dispersion (fire); often heat-treated for color. |
| Tanzanite | Calcium aluminum hydroxyl silicate (Zoisite) | 6.5–7 | Orthorhombic | 1.69–1.70 | 3.35 | Pleochroic (shows different colors from different angles); typically heat-treated. |
Turquoise has a relatively low hardness, making it susceptible to scratches and abrasion. It is also porous, which means it can absorb oils, lotions, and chemicals, potentially altering its color and luster. For this reason, most commercial turquoise is stabilized with a resin or wax to improve durability and color retention. The stone's color ranges from sky blue to bluish-green, and its value is often determined by color, matrix pattern, and origin.
Zircon is one of the hardest natural gemstones, with a hardness approaching that of topaz. Its high refractive index and dispersion (the ability to split light into spectral colors) give it a brilliance and fire that rivals diamond. However, zircon can be brittle due to its perfect cleavage in one direction, making it susceptible to chipping if struck. The blue variety is almost always the result of heat treatment, as natural blue zircon is exceedingly rare. When properly cut, zircon displays exceptional sparkle.
Tanzanite has a hardness of 6.5 to 7 on the Mohs scale, making it suitable for jewelry but requiring care to avoid scratches. Its most remarkable property is pleochroism—when viewed from different angles, it can appear blue, violet, or burgundy. Master cutters orient the stone to display the most desirable blue color from the top. Like zircon, tanzanite is often heat-treated, but this is an accepted and permanent process that enhances the stone's natural beauty. It is also relatively brittle and can be damaged by sharp blows.
Symbolism and Metaphysical Beliefs
Beyond their physical properties, these December gems are imbued with a rich array of symbolic meanings and metaphysical beliefs, many of which have persisted for centuries.
Turquoise has long been associated with protection, healing, and good fortune. In ancient Persia, it was worn as an amulet to guard against unnatural death and was believed to break when it had protected its wearer from danger. For many Native American cultures, turquoise represents the sky and water, and is considered a sacred stone that connects the wearer to the spiritual world. It is often used in healing rituals and is believed to promote emotional balance, creativity, and tranquility. Modern crystal healing practices attribute to turquoise the ability to align the chakras and foster a sense of peace and grounding.
Zircon is traditionally linked to prosperity, honor, and wisdom. In the Middle Ages, it was thought to bring rest and ward off evil. Some legends suggest that zircon can help its owner achieve wisdom and spiritual insight. The blue variety, in particular, is associated with clarity of thought and communication. Metaphysically, it is believed to stimulate the throat and brow chakras, enhancing self-expression and intuition. Its brilliant fire is seen as a symbol of inner light and enlightenment.
Tanzanite, as a modern gemstone, has developed its own set of metaphysical associations. It is often called the "stone of transformation" and is believed to facilitate a higher consciousness and spiritual awakening. Its unique trichroic nature (showing blue, violet, and red) is said to represent the connection between the physical and spiritual realms. Some believe that tanzanite can open the third eye and crown chakras, promoting psychic abilities and a deeper understanding of one's purpose. While these beliefs are not scientifically proven, they contribute to the stone's allure and personal significance for many wearers.
Custom Gold Birthstone Jewelry: A Modern Tradition
The tradition of wearing birthstone jewelry has evolved into a highly personalized practice, particularly with the advent of customizable gold necklaces. These pieces allow individuals to celebrate not only their own birth month but also the birth months of loved ones, creating a tangible symbol of family bonds and personal history.
Modern jewelry retailers offer a range of options for creating custom birthstone necklaces. Metal choices typically include gold-filled, gold vermeil, and solid gold. Gold-filled jewelry, as described in the sources, consists of a thick layer of gold bonded to a base metal core, making it durable and affordable for everyday wear. Gold vermeil (pronounced "ver-may") features a thick layer of gold over sterling silver, offering a more substantial feel and greater longevity than standard gold plating. Both options provide the luxurious appearance of solid gold at a more accessible price point.
Customization is the heart of these pieces. Customers can select from a variety of gemstones—often including the December birthstones tanzanite, turquoise, and zircon—and arrange them in a specific order. This could be chronological, representing the birth order of family members, or purely aesthetic, based on color harmony. The stones are typically set in secure bezels or connector settings, ensuring they are protected while remaining the focal point of the necklace. Chain lengths are customizable, commonly ranging from 14 to 20 inches, allowing for a perfect fit. The dainty cable chain style mentioned in the sources is particularly popular, as it provides a delicate backdrop that lets the stones shine.
When selecting a custom gold birthstone necklace, it is essential to consider the gemstone's properties. For instance, while turquoise and tanzanite are beautiful, their relative softness and brittleness mean they require careful handling. A bezel setting, which encircles the stone with a metal rim, offers more protection than a prong setting for these gems. The sources note that gold-filled jewelry is suitable for everyday wear, including showering and sleeping, but recommend removal for swimming in pools or the sea, as chlorine can damage both the metal and the gemstones.
Care and Cleaning for December Birthstones
Proper care is vital to maintain the beauty and longevity of jewelry featuring tanzanite, turquoise, and zircon. Each stone has specific requirements based on its physical properties.
Turquoise Care: Due to its porosity and low hardness, turquoise requires gentle handling. Clean it with a soft, dry cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals, including household cleaners and lotions, which can penetrate the stone and cause discoloration or damage the stabilizing treatment. Store turquoise separately from other jewelry to prevent scratches. Prolonged exposure to direct sunlight or heat can also fade its color, so it should be kept in a cool, dark place when not worn.
Zircon Care: Zircon's hardness makes it relatively durable, but its perfect cleavage means it can chip if struck. Clean it with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes, which can cause fractures. While zircon is generally stable, the blue variety's color can be affected by prolonged exposure to strong heat or radiation, so it's best to keep it away from extreme environments.
Tanzanite Care: With a hardness of 6.5–7, tanzanite is suitable for daily wear but should be protected from hard impacts. It is also sensitive to rapid temperature changes, which can cause thermal shock and cracking. Clean tanzanite with warm, soapy water and a soft brush. Never use an ultrasonic cleaner or steam cleaner, as the vibrations and heat can damage the stone. Due to its pleochroism, tanzanite should be oriented correctly during setting to ensure the best color display from the top of the stone.
For all custom gold birthstone necklaces, the general advice is to put jewelry on last when dressing and take it off first when undressing. This minimizes exposure to cosmetics, perfumes, and physical abrasion. Regular inspections by a professional jeweler can help ensure the settings are secure and the stones are in good condition.
Conclusion
The December birthstones—tanzanite, turquoise, and zircon—offer a remarkable study in contrast, from the ancient, earthy tones of turquoise to the fiery brilliance of zircon and the modern, celestial hues of tanzanite. Each gem carries a unique geological story, a rich cultural history, and a set of physical properties that influence its use in jewelry. The tradition of wearing these stones has been beautifully adapted into the modern practice of customizing gold birthstone necklaces, allowing for personal expression and the celebration of familial connections. Whether chosen for their aesthetic beauty, symbolic meaning, or historical significance, these gems continue to captivate and inspire. Understanding their origins, properties, and care requirements deepens the appreciation for these natural treasures and the artistry involved in transforming them into cherished heirlooms.