For those born in the final month of the year, the question of a single birthstone does not have a simple answer. December is uniquely associated with four distinct blue gemstones: Turquoise, Tanzanite, Blue Topaz, and Zircon. This abundance of choice reflects a fascinating evolution in gemstone history, where tradition meets modern discovery and commercial appeal. Each of these gems possesses a unique geological origin, a rich history, and a set of gemological properties that dictate its use in jewelry and its care. From the ancient, opaque turquoise cherished by pharaohs to the brilliant, diamond-like sparkle of zircon, the birthstones of December offer a spectrum of colors and meanings, all unified by the cool, serene hues of winter. This article delves into the history, properties, symbolism, and sources of these four celebrated gemstones, providing a comprehensive guide for enthusiasts, collectors, and anyone captivated by the allure of blue gemstones.
History and Lore: From Ancient Talismans to Modern Additions
The history of December’s birthstones is a story of expansion, where ancient traditions have been supplemented by modern discoveries and commercial considerations. The two oldest stones on the list, Turquoise and Zircon, have been revered for millennia, while Tanzanite and Blue Topaz are more recent additions to the birthstone canon, their inclusion reflecting changing tastes and market dynamics.
Turquoise is one of the most ancient gemstones known to humanity. Its history stretches back over 5,000 years, with archaeological 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 the stone has been a staple in Persian, Native American, and Southwestern American jewelry for centuries. The stone’s name is believed to derive from the French phrase pierre turquoise, meaning "Turkish stone," as it was first brought to Europe through Turkish bazaars. Its lore is rich with protective and healing properties. In the 13th century, it was believed to protect the wearer from falls, particularly from horses, and would break into several pieces to warn of impending disaster. Hindu mystics believed that seeing a turquoise after beholding the new moon ensured fantastic wealth. For many Native American tribes, such as the Apache, turquoise was a sacred stone, believed to be found at the end of a rainbow. Shakespeare even referenced its symbolism in The Merchant of Venice, where a turquoise ring is used as a love charm. This long history and deep cultural integration cemented turquoise as a traditional December birthstone.
Zircon, another ancient stone, has a history that is often confused due to its similarity in name to the synthetic cubic zirconia. However, natural zircon is one of the oldest minerals on Earth, with deposits found in Australia dating back billions of years. For centuries, zircon was a popular gemstone in Europe and Asia, valued for its brilliance and fire. It was often mistaken for diamond due to its high refractive index and strong dispersion. In the 19th century, blue zircon became particularly fashionable in Victorian England. Its inclusion in the December birthstone list was formalized in 1952 when the Jewelry Industry Council of America updated the official list, adding zircon to December’s offerings. This addition provided a durable and brilliant alternative to turquoise, appealing to those seeking a classic, diamond-like gem.
The modern era brought two new gems to the December lineup. Tanzanite was discovered in the late 1960s in the Merelani Hills of Tanzania, a unique location that remains the only source for this gemstone. Its vibrant violet-blue to deep blue color, coupled with its strong pleochroism (the property of showing different colors from different viewing angles), quickly captivated the gem and jewelry world. Recognizing its growing popularity and unique origin, the Jewelry Industry Council of America added tanzanite to the official birthstone list in 2002. Its symbolism is often linked to transformation, intuition, and spiritual growth, reflecting its modern, almost mystical, discovery.
Blue Topaz represents the most recent and commercially driven expansion of the December birthstone list. While topaz has been known since antiquity, naturally occurring blue topaz is exceptionally rare. The blue topaz found in today’s market is almost always the result of treating colorless topaz with radiation and heat to achieve its stunning blue hues. Over time, this treated blue topaz gained immense popularity, particularly in the United States, due to its affordability, durability, and wide range of attractive colors. As noted in the sources, it is now "frequently treated as a mainstream December birthstone." While not originally part of the traditional list, its inclusion offers consumers more flexibility in price, durability, and style. The expansion of the list, as one source suggests, may have been to add more affordable options, and blue topaz perfectly fulfills that role.
The standardization of birthstones began in 1912 with the National Association of Jewelers, which aimed to combine customs with gemstones practical for jewelry companies to sell. The subsequent updates in 1952 and 2002 demonstrate that the birthstone list is not static but evolves with new discoveries and market trends. Consequently, when asking for December’s birthstone, the answer can vary, but the four gems—Turquoise, Tanzanite, Blue Topaz, and Zircon—are the universally recognized options today.
Geological Formation and Sources
The origins of these four gemstones are as diverse as their histories. Each forms under specific geological conditions and is mined from distinct regions around the world, contributing to its rarity and value.
Turquoise is a secondary mineral that forms in arid or semi-arid environments. It is not found in primary igneous or metamorphic rocks but rather in the near-surface zone where groundwater percolates through rocks containing copper, aluminum, and phosphorus. The copper gives turquoise its characteristic blue color, while iron imparts a greenish tint. The stone is often found in nodules or veins within host rock, and the remnants of this rock, known as "matrix," are frequently visible as black or brown web-like patterns within the turquoise. Major sources of turquoise include the United States (particularly Arizona and New Mexico), Iran, China, and Egypt. The stone's formation process makes it a relatively soft and sometimes porous gem, which influences its durability and care requirements.
Tanzanite is a geological rarity, found in only one location on Earth: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This single-source origin makes it significantly rarer than diamond. It forms in the metamorphic rocks of the East African Orogeny, a mountain-building event that created the conditions for the formation of the mineral zoisite, to which tanzanite belongs. The intense violet-blue color of tanzanite is caused by trace amounts of vanadium within its crystal structure. The limited geographic area of its discovery and the challenges associated with mining in this region contribute to its status as the most valuable and expensive of the four December birthstones.
Blue Topaz is a silicate mineral that forms in pegmatites and high-temperature veins. While topaz occurs in various colors naturally, the vivid blue varieties that dominate the market are almost exclusively the product of treatment. Colorless or lightly colored topaz, mined primarily in Brazil, Sri Lanka, Nigeria, Mexico, and the United States (Texas), is exposed to gamma radiation to alter its crystal lattice and produce blue color. Subsequent heating stabilizes the color. This treatment process is a standard industry practice and is what makes blue topaz widely available and affordable. As the official state gem of Texas, blue topaz has a significant mining history in the U.S. Its durability and consistent supply from treated material have made it a staple in the jewelry market.
Zircon is a zirconium silicate (ZrSiO₄) and is one of the oldest minerals on Earth. It forms in igneous rocks, such as granite and syenite, and in metamorphic rocks. Zircon crystals are highly durable and resistant to chemical and physical weathering, which is why they are often found as detrital grains in sedimentary deposits. Major sources of gem-quality zircon include Australia (which produces a significant portion of the world’s supply), Cambodia, Sri Lanka, Thailand, and Nigeria. While zircon is available in a range of colors, the brilliant blue varieties are particularly prized for December birthstone jewelry. It is important to note that zircon is a natural gemstone, distinct from the synthetic cubic zirconia (CZ), which is a diamond simulant.
The following table summarizes the key sources for each December birthstone, as derived from the provided materials:
| Gemstone | Primary Mining Locations |
|---|---|
| Turquoise | United States (Arizona, New Mexico), Iran, China, Egypt |
| Tanzanite | Tanzania (Merelani Hills, near Mount Kilimanjaro) |
| Blue Topaz | Brazil, Sri Lanka, Nigeria, Mexico, United States (Texas) |
| Zircon | Australia, Cambodia, Sri Lanka, Thailand, Nigeria |
Gemological Properties
Understanding the physical and optical properties of these gemstones is crucial for jewelers and consumers alike, as these characteristics determine their durability, appearance, and care requirements. The four December birthstones vary significantly in hardness, clarity, and optical effects.
Turquoise is a phosphate mineral with a hardness of 5 to 6 on the Mohs scale, making it one of the softer gemstones used in jewelry. It is typically opaque to semi-translucent, and its color ranges from sky blue to greenish-blue, often with a matrix of the host rock visible. Due to its porosity, turquoise is susceptible to discoloration from oils, pigments, and chemicals, and its color can change if it loses moisture. It is best suited for jewelry that is not subjected to daily knocks, such as necklaces, pendants, and earrings.
Tanzanite belongs to the zoisite mineral group and has a hardness of 6 to 7 on the Mohs scale. It is known for its strong pleochroism, displaying different shades of blue and violet from different crystal directions. This property requires skilled cutting to maximize the stone’s color and brilliance. Tanzanite is typically transparent and can be found in large sizes, making it suitable for statement pieces. Due to its moderate hardness and potential for cleavage, protective settings are recommended for rings.
Blue Topaz is an aluminum silicate fluoride hydroxide mineral and is the hardest of the four December birthstones, with a Mohs hardness of 8. This makes it exceptionally durable and resistant to scratching, ideal for everyday wear, especially in rings. The blue color is achieved through treatment, resulting in shades such as Sky Blue, Swiss Blue, and London Blue. It is typically transparent and can be cut into large, flawless gems. Its high hardness and clarity make it a versatile choice for a wide range of jewelry styles.
Zircon is a zirconium silicate with a hardness ranging from 6.5 to 7.5 on the Mohs scale, placing it between tanzanite and blue topaz in durability. It has a high refractive index (1.92–2.01) and strong dispersion, giving it exceptional brilliance and fire that can rival diamond. Zircon is typically transparent and can be found in a variety of colors, with blue being the most popular for December. However, it is somewhat brittle and can be prone to chipping if struck, so it requires careful handling and protective settings, particularly in rings.
The following table provides a comparative overview of the gemological properties of the four December birthstones, based on the data from the sources:
| Gemstone | Chemical Composition | Mohs Hardness | Key Optical Properties | Typical Clarity |
|---|---|---|---|---|
| Turquoise | Hydrated copper/aluminum phosphate | 5 – 6 | Opaque, often with matrix | Opaque to semi-translucent |
| Tanzanite | Calcium aluminum hydroxyl silicate | 6 – 7 | Pleochroic (blue/violet) | Transparent |
| Blue Topaz | Aluminum silicate fluoride hydroxide | 8 | Transparent, treated for color | Transparent, often flawless |
| Zircon | Zirconium silicate (ZrSiO₄) | 6.5 – 7.5 | High refractive index, high dispersion | Transparent, can have inclusions |
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, each of the December birthstones carries a legacy of symbolic meaning and metaphysical belief, passed down through centuries of folklore and cultural tradition.
Turquoise is perhaps the most storied of the four in terms of symbolism. Universally, it has been regarded as a stone of protection, healing, and friendship. Its association with safety is ancient, from the belief that it could prevent falls to its use as a talisman against evil and negative energy. In many cultures, turquoise is also linked to good fortune, prosperity, and health. The Apache belief that it could be found at the end of a rainbow ties it to luck and divine guidance. As a gift, turquoise symbolizes affection and enduring friendship, a belief immortalized in Shakespearean literature.
Tanzanite, as a modern discovery, has accumulated a more contemporary set of metaphysical associations. It is often linked to transformation, intuition, and spiritual growth. Its striking violet-blue color is said to connect the wearer to higher consciousness and facilitate a deeper understanding of one’s purpose. Some believe tanzanite can stimulate the throat and third-eye chakras, enhancing communication and psychic abilities. Its symbolism reflects its unique origin and the sense of wonder it inspires.
Blue Topaz is associated with clarity, communication, and calmness. Its clear, serene blue hue is believed to promote peacefulness, reduce stress, and enhance honest communication. It is sometimes called the "stone of truth," thought to aid in self-expression and the articulation of thoughts and feelings. Its durability and clear appearance make it a symbol of stability and mental clarity.
Zircon is traditionally linked to wisdom, prosperity, and good fortune. In many cultures, it is considered a stone of honor and purity. Its brilliant sparkle is said to inspire ambition and aid in achieving goals. Some beliefs hold that zircon can promote restful sleep and ward off nightmares. Its historical association with diamonds further reinforces its symbolism of wealth and success.
While these metaphysical beliefs are not scientifically proven, they form an integral part of the cultural heritage of these gemstones, adding a layer of personal meaning for those who wear them.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone jewelry. The varying hardness and stability of the December birthstones require specific handling and cleaning methods.
Turquoise, with its low hardness (5–6) and potential porosity, is the most delicate of the four. It must be protected from chemicals, high heat, and ultrasonic cleaners, which can strip its natural oils, cause discoloration, or even crack the stone. Clean turquoise jewelry with a soft, damp cloth and mild soap, then dry it thoroughly. It is best worn in pieces that are not exposed to daily knocks, such as pendants or earrings, rather than as a ring worn on the hand.
Tanzanite has a moderate hardness (6–7) but can be susceptible to cleavage. It is also sensitive to rapid temperature changes. While it can be cleaned with warm, soapy water and a soft brush, it should not be subjected to ultrasonic or steam cleaners. Protective settings are advisable for rings to prevent impact damage.
Blue Topaz is the most durable of the group, with a hardness of 8. It is resistant to scratching and can withstand daily wear. It can be safely cleaned with warm, soapy water, an ultrasonic cleaner (for most settings), or a steam cleaner. However, as with all gemstones, avoid sudden temperature shocks and harsh chemicals.
Zircon, while hard (6.5–7.5), is relatively brittle and can chip if struck. It is also sensitive to heat and can lose its color if subjected to high temperatures. Clean zircon with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam, as the vibrations or heat can cause fractures. Store zircon jewelry separately from other pieces to prevent scratching and impact.
In summary, while blue topaz offers the greatest ease of care, the other three stones require more attention. Understanding these properties ensures that each gemstone can be enjoyed for generations.
Conclusion
The birthstones of December—Turquoise, Tanzanite, Blue Topaz, and Zircon—offer a remarkable diversity of history, geology, and symbolism. From the ancient, protective turquoise to the rare, transformative tanzanite, the clear, communicative blue topaz, and the brilliant, prosperous zircon, each gem tells a unique story. Their shared blue color palette connects them to the winter season, providing a spectrum of choices for those born in this month. The evolution of the birthstone list, incorporating both ancient traditions and modern discoveries, reflects the dynamic nature of gemology and jewelry. Whether selected for its historical significance, its unique origin, its durability, or its symbolic meaning, any of these four stones makes a meaningful and beautiful choice, capturing the essence of December in its cool, captivating hues.