December holds a unique distinction in the world of gemstones. While most months are associated with a single birthstone, December boasts four officially recognized gems: turquoise, zircon, tanzanite, and blue topaz. This abundance reflects the month’s rich tapestry of cultural traditions and the evolving nature of gemstone lore. All four stones share a common color theme—a cool, wintry palette of blues that mirrors the icy skies and deep twilight of the winter season. Yet, each gem possesses its own distinct history, geological origin, gemological properties, and symbolic meaning. From ancient amulets to modern masterpieces, these stones have been treasured across millennia and continents. This article delves into the stories, science, and symbolism of December’s four birthstones, offering a detailed exploration for enthusiasts, collectors, and anyone captivated by the beauty of these remarkable minerals.
History and Lore: From Ancient Amulets to Modern Additions
The tradition of assigning specific gemstones to months is believed to have ancient roots, originating in Mesopotamia and later adopted by the Greeks and Romans. The December birthstone list, however, has not been static. It has evolved over time, reflecting new discoveries and shifting cultural preferences.
Turquoise: The Ancient Guardian Turquoise is the oldest and most traditional of December’s birthstones, with a history spanning over 5,000 years. Ancient miners first discovered it in Egypt’s Sinai Peninsula, where it was carved into jewelry, amulets, and ornaments for pharaohs. The famous burial mask of King Tutankhamun is adorned with turquoise details that remain vibrant after millennia. In Persia (modern-day Iran), turquoise was revered as the color of the heavens. Persian kings decorated their palaces with turquoise tiles, believing the stone would connect their structures to the sky and bring victory and good fortune. Traders carried the gem along the Silk Road to Europe, where it became known as “Turkish stone.”
On the other side of the world, Native American tribes—including the Navajo, Zuni, and Pueblo peoples—deeply valued turquoise, seeing it as a gift from the sky. Across these cultures, turquoise was consistently associated with protection, good health, and good luck. It was used in amulets and talismans to ward off negative energies and promote wisdom, tranquility, and enhanced communication. The most prized variety is Persian turquoise, celebrated for its vivid sky-blue color and minimal matrix (the dark veins that can appear in the stone). Another highly valued type is Sleeping Beauty Turquoise, known for its pure, robin’s-egg blue color and smooth, uniform appearance, mined exclusively from the Sleeping Beauty Mine in Arizona before its closure.
Zircon: A Sparkling Blue Classic Zircon, in its blue form, has also been part of the December tradition for centuries. It is one of the oldest minerals on Earth, with crystals found in geological formations dating back over 4.4 billion years. The name “zircon” comes from the Arabic word zarkun, meaning “gold-like,” a reference to the yellowish or reddish tones of some zircon varieties. Historically, blue zircon was valued for its brilliance and fire, making it a popular alternative to diamonds in jewelry. It was used in ancient cultures and has been rediscovered in modern times as a durable and affordable gemstone. The blue color is achieved through heat treatment, which transforms the gem from a brown or yellow hue into a vibrant blue. Zircon’s inclusion in the official December birthstone list was formalized in 1952 by the Jewelry Industry Council of America, adding it to the traditional stones of turquoise and tanzanite.
Tanzanite: The Modern Marvel Tanzanite is the most recent addition to the December birthstone family, recognized in 2002. It was discovered in the Merelani Hills of Tanzania in 1967 and quickly captivated the gem world with its unique violet-blue hue and trichroic properties (displaying different colors when viewed from different angles). Its rapid rise to prominence was bolstered by a major jewelry brand’s marketing campaign, which linked the gem to the month of December. Tanzanite’s story is one of modernity and rarity, as it is found in only one location on Earth.
Blue Topaz: The Durable and Affordable Option Blue topaz became a recognized December birthstone in the 20th century. Its exact historical origin is unknown, as it has been found throughout history, but it gained popularity as a durable and affordable option for jewelry. The addition of blue topaz, along with zircon and tanzanite, expanded the December palette, offering a wider variety of colors and styles. This expansion reflects the evolving nature of the birthstone tradition, influenced by new gemstone discoveries and commercial appeal.
The standardization of birthstones in the United States began in 1912 with the National Association of Jewelers, which combined customs with gemstones practical for jewelry companies to sell. The list has been updated several times since, with zircon added in 1952 and tanzanite in 2002, solidifying December’s status as the month with the most birthstone options.
Geological Formation and Sources
Each of December’s four birthstones forms under distinct geological conditions and is sourced from specific regions around the world.
Turquoise Turquoise is a secondary mineral formed in arid regions where acidic, copper-rich groundwater percolates through rocks containing aluminum and phosphorus. Over millions of years, these minerals crystallize in veins and nodules. Major sources include: - Iran (Persia): Historically the most significant source for high-quality, vivid sky-blue turquoise with minimal matrix. - United States: Particularly Arizona and New Mexico. The Sleeping Beauty Mine in Arizona was famous for its pure, robin’s-egg blue turquoise before its closure. Other notable U.S. sources include the Kingman and Morenci mines. - Other Locations: Turquoise is also mined in China, Tibet, Mexico, and Afghanistan, each producing stones with unique characteristics.
Zircon Zircon is a mineral formed in igneous and metamorphic rocks. It is commonly found in granites and syenites, and as a detrital mineral in sands and gravels. Blue zircon, however, is almost exclusively the result of heat treatment applied to brown or yellow zircon crystals. Major sources for zircon crystals include: - Sri Lanka: A traditional source for zircon, including varieties that can be treated to blue. - Cambodia: Known for producing high-quality zircon crystals. - Australia: A significant source of zircon, particularly for industrial use, but also for gemstones. - Other Locations: Zircon is also found in Myanmar, Brazil, and Nigeria.
Tanzanite Tanzanite is unique in that it is found in only one location on Earth: the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. It forms in the presence of heat and pressure from metamorphic processes, specifically within the geological formation known as the “Merelani Formation.” The gem is a variety of the mineral zoisite and gets its blue-violet color from trace amounts of vanadium. Due to its singular source, tanzanite is considered one of the rarest gemstones, making it highly valuable.
Blue Topaz Blue topaz is a variety of the mineral topaz, which forms in igneous rocks like granite and rhyolite. The natural blue color in topaz is very rare; most commercial blue topaz is created by irradiating colorless topaz and then heating it to produce a stable blue hue. Major sources for topaz (including material used for blue topaz) include: - Sri Lanka - Brazil - Mexico - Nigeria - United States: Particularly in Texas, where blue topaz is the official state gem.
Gemological Properties
The physical and optical characteristics of these gemstones vary significantly, influencing their durability, appearance, and care requirements.
| Gemstone | Chemical Composition | Mohs Hardness | Crystal System | Key Properties |
|---|---|---|---|---|
| Turquoise | Hydrated copper aluminum phosphate | 5–6 | Triclinic | Often porous, can be dyed or stabilized. Color ranges from sky blue to greenish-blue. |
| Zircon | Zirconium silicate | 6.5–7.5 | Tetragonal | High refractive index and strong dispersion ("fire"). Blue color is typically from heat treatment. |
| Tanzanite | Calcium aluminum hydroxyl sorosilicate | 6–7 | Orthorhombic | Trichroic (shows blue, violet, and burgundy). Color is natural from vanadium. |
| Blue Topaz | Aluminum fluorosilicate | 8 | Orthorhombic | Color is almost always from irradiation and heat treatment. High durability for everyday wear. |
Turquoise Turquoise has a Mohs hardness of 5 to 6, making it relatively soft and susceptible to scratching and chemicals. It is often porous, so it is commonly treated (dyed, stabilized with wax or resin) to enhance color and durability. Its color ranges from soft sky blue to greenish hues, often with a characteristic matrix (web-like patterns of host rock).
Zircon With a Mohs hardness of 6.5 to 7.5, zircon is durable enough for most jewelry, though it can be brittle. It possesses a high refractive index and strong dispersion, giving it exceptional brilliance and fire, rivaling that of diamond. The blue color in gem-quality zircon is almost always the result of heat treatment applied to brown or yellow crystals.
Tanzanite Tanzanite has a Mohs hardness of 6 to 7. It is known for its strong trichroism, displaying three different colors: blue, violet, and burgundy red, depending on the crystal orientation. The gem’s captivating blue-violet hue is natural, caused by trace amounts of vanadium. It is pleochroic, meaning its color intensity can vary with the viewing angle.
Blue Topaz Blue topaz is the hardest of the December birthstones, with a Mohs hardness of 8, making it highly durable for everyday wear. Its color is almost exclusively the result of treatment; natural blue topaz is exceedingly rare. The treated stones can range from pale sky blue (often called "Swiss Blue") to deeper, more saturated blues.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December’s birthstones are imbued with rich symbolism and metaphysical beliefs that have been passed down through generations.
Turquoise is universally regarded as a stone of protection, grounding, and calm. It is believed to ward off negative energy, promote inner peace, and enhance communication. In many cultures, it is seen as a symbol of good fortune and health. Its steadying force is often sought during times of chaos or stress.
Tanzanite is associated with transformation, new beginnings, and spiritual growth. Its shifting blue-violet tones are thought to reflect a journey of self-discovery and clarity. It is often linked to the crown chakra and is believed to facilitate higher consciousness and intuition.
Zircon is known for its properties of mental clarity, focus, and wisdom. It is believed to sharpen the mind, boost concentration, and promote a sense of balance and stability. Some traditions also associate it with prosperity and honor.
Blue Topaz, particularly in its deeper shades, is associated with calm, clarity, and communication. It is believed to soothe emotions, reduce stress, and aid in expressing thoughts and feelings clearly. It is also linked to truth and forgiveness.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, given their varying physical properties.
Turquoise Due to its relative softness and porosity, turquoise requires gentle care. It should be cleaned with a soft, dry cloth. Avoid exposing it to chemicals, including household cleaners, cosmetics, and even sweat, as these can cause discoloration or damage. It is best to remove turquoise jewelry before swimming, bathing, or engaging in strenuous activities.
Zircon Zircon is relatively durable but can be brittle. Clean it with warm water, mild soap, and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes, which can cause fracturing. Store it separately to prevent scratching by harder gems.
Tanzanite With a hardness of 6 to 7, tanzanite is more durable than turquoise but still requires care. It is best cleaned with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as the heat and vibrations can damage the stone. Due to its popularity and value, it is advisable to have tanzanite jewelry inspected regularly by a professional.
Blue Topaz As the hardest of the group (Mohs 8), blue topaz is quite durable and suitable for daily wear. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided as heat can potentially damage some treated stones. Its durability makes it an excellent choice for rings and bracelets that see frequent use.
Conclusion
December’s four birthstones—turquoise, zircon, tanzanite, and blue topaz—offer a remarkable diversity of history, geology, and symbolism. From the ancient protective amulets of turquoise to the modern rarity of tanzanite, each gem tells a unique story. Their shared blue hues connect them to the winter season, yet their individual characteristics provide a wide range of options for personal expression and jewelry design. Understanding their origins, properties, and care requirements allows enthusiasts and collectors to appreciate these gems on a deeper level. Whether drawn to the historical significance of turquoise, the brilliant fire of zircon, the captivating color shift of tanzanite, or the durable beauty of blue topaz, there is a December birthstone to suit every preference and style, making this month truly a small treasure chest of gemological wonders.