December holds a unique distinction in the world of birthstones, being the only month officially associated with four distinct gemstones. This abundance offers a remarkable spectrum of blue hues, each reflecting the cool, crisp essence of winter. The four recognized birthstones for December are Turquoise, Zircon, Tanzanite, and Blue Topaz. While they share a common color palette reminiscent of icy skies and deep twilight, each gem possesses its own unique geological origin, gemological properties, historical lore, and journey to becoming a part of this celebrated tradition. This article provides an in-depth exploration of these four remarkable stones, delving into their history, formation, properties, and symbolism.
The Historical Evolution of December's Gems
The tradition of assigning specific gemstones to months has ancient roots, believed to have originated in Mesopotamia and later adopted by the Greeks and Romans. The modern list of birthstones, however, is a product of more recent standardization. The initial formalization occurred in 1912 when the National Association of Jewelers (now the Jewelers of America) sought to create a standardized list for the American market. This list combined historical customs with gemstones that were practical for jewelry companies to sell and consumers to acquire.
Initially, the December list was more limited. Over time, it evolved to include new discoveries and commercially appealing stones. In 1952, the Jewelry Industry Council of America updated the list, adding Zircon to December’s options. The most recent addition was Tanzanite in 2002. This expansion reflects the dynamic nature of the birthstone tradition, accommodating both ancient gems and modern discoveries. Some sources suggest that the proliferation of stones for December may also have been to offer consumers a wider variety of colors, styles, and price points, ensuring there is a suitable option for every preference and budget.
Turquoise: An Ancient Talisman of Protection and Wisdom
Turquoise is arguably one of the most ancient and culturally significant gemstones known to humanity. Its history spans millennia, with evidence of its use dating back to ancient Egypt, where it was used in jewelry and funerary ornaments, and in Mesopotamia. It was cherished by royalty across the globe, most famously adorning the burial mask of the Egyptian Pharaoh King Tutankhamun. For centuries, Turquoise has been a symbol of protection, wisdom, tranquility, and good fortune. It was believed to safeguard its wearer from harm, including falls and negative energy, and to promote health and well-being. Today, its symbolism has evolved to encompass wisdom, tranquility, and friendship.
Geological Formation and Sources
Turquoise is an opaque, hydrous phosphate of copper and aluminum. It is not a crystalline mineral but forms in masses as water-rich solutions percolate through rocks rich in aluminum and copper. This process occurs in arid regions where specific geological and weather conditions facilitate its formation. The most significant sources of Turquoise include the southwestern United States (particularly Arizona and New Mexico), Iran, Egypt, China, Mexico, and parts of Central Asia and Africa.
The appearance of Turquoise is often characterized by a "matrix," which are dark veins of host rock trapped within the gem. The value of a Turquoise stone is often determined by the color and the amount of matrix. A highly valued type is that from the Sleeping Beauty Mine in Arizona, known for its pure, uniform "robin's-egg blue" color with minimal matrix. The mine's closure has made such stones increasingly prized.
Gemological Properties
As a non-crystalline mineral, Turquoise has a relatively low hardness on the Mohs scale, typically ranging from 5 to 6. This makes it susceptible to scratches and damage, and it requires careful handling. Its color ranges from sky blue to greenish-blue, depending on the amount of copper (blue) and iron (green) present in its chemical composition. Its opaque nature means that clarity is not a grading factor; instead, color and texture are paramount.
Care and Cleaning
Due to its moderate hardness and potential porosity, Turquoise jewelry should be handled with care. It is not ideal for daily wear, especially in rings or bracelets that are prone to impact. To clean it, use warm, soapy water and a soft brush. Avoid harsh chemicals, ultrasonic cleaners, and steam, as these can damage the stone or its stability treatments.
Zircon: A Sparkling Blue Classic with Ancient Roots
Zircon is one of the oldest minerals on Earth, with crystals found in geological formations dating back over 4.4 billion years. Its name is derived from the Arabic word zarkun, meaning "gold-like," a reference to the yellowish or reddish tones of some natural zircon varieties. While Zircon occurs in a range of colors, the bright, clear blue variety has been a part of the December birthstone tradition for centuries. Blue Zircon was historically valued for its exceptional brilliance and fire, making it a popular and dazzling alternative to diamonds in jewelry.
Geological Formation and Sources
Zircon is a silicate mineral (zirconium silicate, ZrSiO₄) that forms in igneous and metamorphic rocks. It is highly resistant to weathering and is often found as detrital grains in sedimentary deposits. The vibrant blue color seen in most commercial blue Zircon is not typically natural. The gemstone is usually mined in its natural brown or yellow form and then subjected to high-heat treatment, which transforms its color to the desirable blue hue. This process is a standard and accepted practice in the gem trade.
Gemological Properties
Zircon is renowned for its high refractive index, which is greater than that of a diamond, giving it exceptional brilliance and fire. On the Mohs hardness scale, it rates between 6.5 and 7.5, making it reasonably durable for most jewelry types, though it can be brittle. Its strong double refraction can sometimes be observed with the naked eye, causing facets to appear doubled. This property, along with its high dispersion (the "fire" that splits light into spectral colors), makes it a visually captivating gem.
Care and Cleaning
With a hardness of over 7, Zircon is relatively durable but can be brittle. It is best suited for earrings and pendants, which are less likely to receive hard knocks. If used in a ring, it should be set in a protective setting. Cleaning is straightforward: use warm, soapy water and a soft brush. Avoid sudden temperature changes and harsh chemicals.
Tanzanite: The Modern Marvel of a Single Origin
Tanzanite is the newest and most recent addition to the December birthstone family, officially added to the list in 2002. It is a variety of the mineral zoisite and is celebrated for its mesmerizing blue-violet color. Discovered in the 20th century, its story is a modern gemological tale. Tanzanite is prized for its unique pleochroism, displaying different shades of blue and violet depending on the viewing angle. It is associated with transformation, growth, and fresh chapters in life, reflecting its modern origin and striking appearance.
Geological Formation and Sources
Tanzanite’s geological story is as unique as its color. It is found in only one place on Earth: the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. This extremely limited geographic origin makes it thousands of times rarer than diamond. The formation of Tanzanite is linked to a unique geological event where heat and pressure from tectonic plate movements altered the parent rock, introducing vanadium which is responsible for its captivating blue-violet hue.
Gemological Properties
Tanzanite is a relatively soft gemstone, with a Mohs hardness of 6 to 7. This makes it less durable than Zircon or Blue Topaz and requires careful handling. Its most striking feature is its strong trichroic pleochroism, meaning it can show three different colors: blue, violet, and reddish-brown when viewed from different directions. Most of the rough is heat-treated to bring out the stable blue and violet hues. Its color saturation and uniformity are the primary factors in determining its value.
Care and Cleaning
Due to its moderate hardness and potential for brittleness, Tanzanite should be protected from sharp blows and extreme temperature changes. It is an excellent choice for pendants and earrings. To clean, use warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as the vibrations and heat can cause internal fractures.
Blue Topaz: A Durable and Vibrant Modern Option
Blue Topaz is a popular and widely available gemstone that became a recognized December birthstone in the 20th century. It is known for its dazzling, often deep, blue color and its excellent durability. While Topaz occurs naturally in a variety of colors, including yellow, pink, and clear, the blue variety has become synonymous with December. Its association with calmness and communication has made it a beloved choice for jewelry.
Geological Formation and Sources
Topaz is a silicate mineral of aluminum and fluorine (Al₂SiO₄(F,OH)₂). It forms in igneous rocks like granite and rhyolite. The vast majority of blue Topaz on the market begins as a colorless or pale brown topaz crystal. The intense blue color is achieved through irradiation followed by heat treatment, a process that is stable and permanent. This treatment allows for the production of large, clean, and vibrantly colored stones, making it an affordable and accessible gem.
Blue Topaz is mined in several locations worldwide, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States. It is significant enough to be named the official state gem of Texas.
Gemological Properties
Blue Topaz is the most durable of the four December birthstones for everyday wear. It ranks an 8 on the Mohs hardness scale, making it highly resistant to scratching and suitable for all types of jewelry, including rings. It also has good toughness. Its color can range from a pale, sky blue (often called "Sky Topaz") to a deep, saturated blue (known as "London Blue Topaz"). The clarity of Topaz is typically very high, with most gems being eye-clean.
Care and Cleaning
Its high hardness and good toughness make Blue Topaz very easy to care for. It can be safely cleaned with warm, soapy water and a soft brush. It is also generally safe for ultrasonic cleaners, though caution is always advised. Avoid exposing it to extreme heat, as this can damage the stone or alter its color.
Symbolism and Metaphysical Beliefs
Each of the four December birthstones carries a rich tapestry of symbolic meaning and metaphysical belief, offering a diverse range of attributes for those born in this month.
- Turquoise: As mentioned, it is a stone of protection, grounding, and calm. It is believed to bring good fortune and peace to its wearer and is often associated with healing and spiritual balance.
- Zircon: This gem is linked to clarity, wisdom, and mental focus. It is thought to help its wearer achieve a sense of balance and to ward off negative thoughts.
- Tanzanite: With its modern discovery and transformative color, Tanzanite is a stone of new beginnings, spiritual growth, and higher consciousness. It is believed to facilitate a connection to one's higher self and to encourage a positive outlook.
- Blue Topaz: This stone is associated with calmness, clarity, and communication. It is believed to soothe the mind, reduce stress, and promote truthful expression.
Conclusion
The month of December is uniquely endowed with a quartet of gemstones, each offering a distinct shade of blue and a unique story. From the ancient, protective talisman of Turquoise to the billion-year-old sparkle of Zircon, the modern marvel of Tanzanite, and the durable vibrancy of Blue Topaz, these stones provide a wealth of choice for jewelry lovers and gemstone enthusiasts. Their shared color palette evokes the serene beauty of winter, while their individual histories, properties, and meanings ensure that there is a perfect December birthstone for every personality and purpose. Understanding the unique characteristics of each allows for a deeper appreciation of these beautiful gifts from the Earth.