December holds a unique distinction in the world of birthstones. While most months are assigned a single gem, or perhaps a traditional and modern variant, December boasts four officially recognized birthstones: Tanzanite, Turquoise, Zircon, and Blue Topaz. This abundance of choice reflects both the evolving nature of gemological traditions and a deliberate effort to provide a wide spectrum of colors, price points, and styles for those born in the final month of the year. All four gemstones share a common thread: a captivating blue hue that evokes the cool, serene tones of winter. This article provides an in-depth exploration of these four remarkable gems, detailing their histories, geological origins, gemological properties, and cultural significance.
The tradition of associating specific gemstones with birth months has ancient roots, believed to have originated in Mesopotamia and later adopted by the Greeks and Romans. The modern list of birthstones, however, was standardized in the United States in the early 20th century. The National Association of Jewelers established an official list in 1912, which has been updated several times to include new and popular gemstones. December's list has seen the most significant evolution. Originally, only Turquoise and Zircon were recognized. In 1952, the Jewelry Industry Council of America added Zircon to the list, and in 2002, the American Gem Trade Association (AGTA) added Tanzanite, making it the most recent official addition. Blue Topaz, while not on the original traditional lists, has gained immense popularity and is now widely considered a mainstream December birthstone, often included in modern guides. This expansion offers those with December birthdays unparalleled flexibility, allowing them to choose a stone that perfectly matches their personal taste and budget.
History and Lore
The history of December's birthstones is as varied and colorful as the gems themselves, spanning ancient civilizations, modern discoveries, and centuries of trade.
Turquoise: The Ancient Amulet
Turquoise is arguably one of the oldest gemstones in human history, revered for thousands of years for its protective qualities and distinctive color. Its name is derived from the French phrase pierre tourquoise, meaning "Turkish stone," as the gem was first brought to Europe from Turkey via Persian trade routes. However, its origins lie much further east, with ancient mining operations in the Sinai Peninsula and Persia (modern-day Iran). Ancient Egyptians adorned themselves with turquoise, inlaid it into artifacts like Tutankhamun's burial mask, and valued it for its connection to the heavens and the earth.
Beyond the Nile, turquoise held a sacred place in many cultures. For the ancient Persians, it was a symbol of purity and was believed to ward off unnatural death and injury. It was often set into jewelry as a protective talisman. In Native American cultures of the American Southwest, turquoise is a cornerstone of spiritual and artistic life. It is considered a living stone, a piece of the sky that fell to earth, and is central to the jewelry and ceremonial objects of tribes like the Navajo, Zuni, and Hopi. It symbolizes friendship, good fortune, and protection, and is often gifted as a token of these bonds.
Zircon: The Gem of Wisdom and Purity
Zircon is one of the oldest minerals on Earth, with deposits dating back billions of years. For centuries, it was confused with other popular gemstones, most notably diamond, due to its high refractive index and brilliance. The name "zircon" likely comes from the Persian word zargun, meaning "gold-colored," though zircon occurs in a variety of colors. The blue variety, which is the primary birthstone for December, is typically achieved through heat treatment of brown zircon crystals.
Throughout history, zircon has been associated with wisdom, honor, and purity. In the Middle Ages, it was believed to induce sound sleep, ward off evil spirits, and protect travelers. It was also a popular stone for travelers, who believed it would guide them safely on their journeys and ensure a prosperous business trip. The association with wisdom and clarity of thought has made it a stone of scholars and thinkers.
Tanzanite: The Modern Marvel
Of the four December stones, Tanzanite is the most recent addition to the birthstone family and has a fascinatingly brief but dramatic history. It was not discovered until 1967 in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The gem was initially mistaken for sapphire until it was identified as a new variety of the mineral zoisite. Tiffany & Co. recognized its beauty and rarity and launched a major marketing campaign in 1968, naming the gem "tanzanite" after its country of origin. Its popularity soared, and in 2002, it was officially added to the list of birthstones for December.
Tanzanite is often called the "gemstone of a generation" because its single known source is extremely limited, leading to speculation that it may be exhausted within a few decades. This rarity, combined with its captivating color, has cemented its status as a highly sought-after gem. Culturally, it is associated with transformation, new beginnings, and a unique sense of intuition and perception.
Blue Topaz: The Affordable Brilliance
While topaz has been known since antiquity, the vibrant blue variety that is popular today is a more modern phenomenon. Historically, topaz was most prized in its golden-yellow form. The confusion was so widespread that many imperial topaz specimens were actually yellow sapphires or citrines. The brilliant, clear blue of the topaz seen in jewelry today is almost always the result of irradiation and heat treatment applied to colorless or pale topaz crystals.
Blue topaz's rise to prominence as a December birthstone is tied to its affordability, durability, and the sheer beauty of its saturated color. As consumers sought more budget-friendly alternatives to sapphire and aquamarine, blue topaz filled the niche perfectly. It is now one of the most popular blue gems in the market, available in a range of cuts and sizes. Its symbolism is often linked to calmness, clarity, and communication.
Geological Formation and Sources
Understanding where these gems come from reveals why some are so rare and others more accessible.
Turquoise is a secondary mineral that forms when water containing copper, aluminum, and phosphorus seeps through pre-existing rocks. It is found in arid regions where this process occurs over millions of years, filling cavities and cracks in the host rock. Major sources include the United States (specifically Arizona, New Mexico, and Nevada), Iran, Tibet, and Egypt. Persian turquoise from Iran is widely considered the finest quality, known for its intense, even sky-blue color and lack of matrix (the host rock webbing).
Zircon is a mineral belonging to the nesosilicates group. It forms in igneous and metamorphic rocks, such as granite and gneiss. The heat treatment that produces the desirable blue color is a stable and permanent process. Major sources for gem-quality zircon include Australia, Cambodia, Sri Lanka, and Thailand. Australia is a primary source for the brown crystals that are later heated to create blue zircon.
Tanzanite is a variety of the mineral zoisite. Its formation is incredibly unique and localized. It is believed to have been created by a massive geological event, a tectonic shift and metamorphism, that occurred approximately 585 million years ago. This event concentrated the gem-bearing zoisite in a tiny, 4-square-kilometer area in Tanzania. To date, this is the only known commercial source of tanzanite in the world, making it thousands of times rarer than diamond.
Blue Topaz is a silicate mineral with the chemical formula Al₂SiO₄(F,OH)₂. It crystallizes in igneous rocks, particularly in gas pockets in rhyolite lava. The world's primary sources of the pale topaz used for treatment are Brazil, Nigeria, Sri Lanka, and Mexico. The United States, specifically Texas, has also produced some topaz, and blue topaz is the official state gem of Texas.
Gemological Properties
The four December birthstones vary significantly in their physical properties, which directly impacts their durability, care, and suitability for different types of jewelry.
| Gemstone | Mineral Group | Chemical Formula | Mohs Hardness | Durability & Care Notes |
|---|---|---|---|---|
| Blue Topaz | Silicate | Al₂SiO₄(F,OH)₂ | 8 | Good durability for everyday wear. Can be brittle; avoid hard blows. |
| Blue Zircon | Nesosilicate | ZrSiO₄ | 6.5 - 7.5 | Fairly good durability, but can be brittle. Suitable for rings with protective settings. |
| Tanzanite | Zoisite | Ca₂Al₃(SiO₄)₃(OH) | 6.5 | Fair durability, but has poor toughness and distinct cleavage. Best for earrings or pendants. |
| Turquoise | Phosphate | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | Soft and porous. Prone to scratching, chipping, and discoloration. Requires careful handling. |
Color and Clarity
The defining characteristic of these gems is their blue coloration, though its source and appearance differ. * Turquoise's color is caused by copper, ranging from sky blue to greenish-blue. It is often opaque, and its beauty can be enhanced by a contrasting or complementary "matrix" – the web-like remnants of the host rock. * Zircon's brilliant blue is the result of heat treatment. It is known for its high refractive index, which gives it a brilliance and sparkle that can rival diamond. It is typically eye-clean, making it a very brilliant stone. * Tanzanite exhibits a unique and highly sought-after pleochroism, meaning it shows different colors (blue, violet, and burgundy) when viewed from different crystal directions. The most desirable color is a deep, rich violet-blue. * Blue Topaz is prized for its crystal-clear, saturated blue color, which is achieved through treatment. The most popular shades are Swiss Blue (a bright, sky blue) and London Blue (a deep, inky blue).
Durability and Wearability
For jewelry intended for daily wear, such as an engagement ring, hardness and toughness are critical. * Blue Topaz is the most durable of the four, with a Mohs hardness of 8. It is an excellent choice for rings, bracelets, and other pieces that will encounter daily activity. * Blue Zircon, with a hardness of 6.5 to 7.5, is reasonably durable but can be brittle due to its crystal structure. It is suitable for rings, but should be worn with some care to avoid hard impacts. * Tanzanite has a moderate hardness of 6.5, but its main vulnerability is its distinct cleavage, meaning it can split if struck with force. For this reason, it is most often set in protective settings and used for earrings, pendants, and occasional-wear rings. * Turquoise, with a hardness of only 5 to 6, is the softest and most porous of the group. It is susceptible to scratches, chipping, and damage from chemicals, lotions, and even body oils. It is best suited for items like beads, pendants, and earrings that are less likely to be knocked around.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these stones have been imbued with powerful symbolic meanings. * Turquoise is primarily a stone of protection, healing, and good fortune. It is believed to shield the wearer from negative energy, promote inner calm, and aid in communication. It is also a symbol of friendship and wisdom. * Zircon is associated with clarity, wisdom, and honor. It is said to help its owner see things clearly, make wise decisions, and attract prosperity and honor. It is also believed to promote a sense of balance and spiritual grounding. * Tanzanite symbolizes transformation, intuition, and new beginnings. As a relatively new gem, it is associated with modernity and a shift in consciousness. It is believed to stimulate the throat and crown chakras, enhancing communication and spiritual perception. * Blue Topaz is linked to calmness, clarity of thought, and communication. It is considered a soothing stone that can help reduce stress and anxiety. It is also associated with truth and forgiveness, making it a stone of peaceful expression.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of December's birthstones, with requirements varying significantly based on their properties.
- Turquoise: This is the most delicate stone. Clean it only with warm water, a mild soap, and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and any chemicals, including perfumes and lotions, which can cause discoloration or damage. Store it separately to prevent scratching.
- Zircon: Although fairly hard, zircon can be brittle. It is safe to clean with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as the heat and vibrations could potentially damage the stone. Avoid sudden temperature changes.
- Tanzanite: Due to its cleavage and moderate hardness, tanzanite should be cleaned gently with warm, soapy water and a soft brush. It is highly recommended to avoid ultrasonic and steam cleaners. When setting tanzanite, jewelers must exercise extreme care.
- Blue Topaz: With its good hardness, blue topaz is relatively easy to care for. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning is not recommended due to the possibility of thermal shock, which can cause fractures in the stone. As with all gems, it is wise to avoid harsh chemicals.
Conclusion
The four birthstones of December—Tanzanite, Turquoise, Zircon, and Blue Topaz—offer a remarkable range of choices for those born in the last month of the year. From the ancient, protective talisman of Turquoise to the brilliant, diamond-like sparkle of Zircon, the unique, one-source wonder of Tanzanite, and the durable, affordable beauty of Blue Topaz, each gem possesses a distinct character, history, and set of properties. This variety ensures that there is a perfect December birthstone for every individual, whether they are drawn to historical significance, metaphysical beliefs, vibrant color, or modern style. Together, they form a collection that is not only aesthetically diverse but also deeply rooted in the traditions of gemology and human culture.