December is a unique month in the world of birthstones, boasting not one, but four recognized gems: Tanzanite, Turquoise, Blue Zircon, and Blue Topaz. Each of these stones presents a captivating shade of blue, mirroring the cool tones of the winter season. While Turquoise holds the longest tradition as a December birthstone, the inclusion of Tanzanite, Zircon, and Topaz offers a diverse range of options for those born in the final month of the year. This article will delve into the history, geological origins, gemological properties, and symbolism of these four December birthstones, providing a comprehensive overview for enthusiasts and those seeking to understand their significance.
A History of Changing Traditions
The designation of birthstones has evolved over time. Early birthstone lists, inspired by Biblical texts, initially assigned ruby as the stone for December. However, the modern birthstone list has undergone several revisions. Turquoise first appeared as a December birthstone in 1870, as documented in Tiffany & Co.’s “Gregorian Birthstone Poems.” By 1912, the National Association of Jewellers (now Jewellers of America) listed Turquoise as the primary stone, with lapis lazuli as an alternative. Zircon was added to the list in 1952 by the Jewelry Industry Council of America, and most recently, Tanzanite was officially recognized in 2002. This evolution reflects changing tastes, discoveries of new gemstones, and the influence of gemological and commercial interests. The question of the “real” December birthstone is therefore complex, with Turquoise maintaining the most consistent historical presence, while each gem possesses its own unique lore and appeal.
Geological Formation and Sources
Each of the December birthstones originates from distinct geological environments. Turquoise, a hydrated phosphate of copper and aluminum, forms through a secondary enrichment process in arid regions. Significant mining locations include the United States (Arizona, California, Nevada), Mexico, Iran (historically the most valued source), Chile, China, and Tibet. The value of turquoise often depends on its source, with historically prized specimens originating from Iran. Modern turquoise is frequently dyed and stabilized with resins to enhance color and durability.
Blue Zircon is sourced from Thailand, Cambodia, and Vietnam, and is a natural gem, distinct from synthetic cubic zirconia. It is found in a variety of colors, with heat treatment often employed to achieve the desirable pastel blue hue. Interestingly, zircon contains trace amounts of uranium and thorium, making it valuable in radiometric dating, with some specimens calculated to be up to 4.4 billion years old – among the oldest minerals on Earth.
Tanzanite, a relatively recent discovery, is exclusively found in a small area near Mount Kilimanjaro in Tanzania. This unique geographical limitation contributes to its rarity and value. It is a transparent blue crystal, typically faceted into various shapes, exhibiting colors ranging from blue to purple.
Blue Topaz is found in Brazil, Afghanistan, Australia, Myanmar (Burma), China, Germany, Japan, Madagascar, Mexico, Namibia, Nigeria, Pakistan, Russia, Zimbabwe, Sri Lanka, Ukraine, and the USA. Natural light-blue topaz is also found in Northern Ireland and the UK.
Gemological Properties
The four December birthstones exhibit distinct gemological properties.
Turquoise: Its chemical composition is hydrated copper aluminum phosphate [CuAl6(PO4)4(OH)8·4H2O]. It is often opaque and relatively soft, requiring careful handling.
Blue Zircon: Possesses a high refractive index, contributing to its brilliance, and is sometimes used as a diamond substitute. Its chemical formula is ZrSiO4.
Tanzanite: A variety of the mineral zoisite, its pleochroism – displaying different colors from different viewing angles – is a notable characteristic. Its chemical formula is Ca2Al3(SiO4)3(OH).
Blue Topaz: A silicate mineral containing aluminum and fluorine, it is known for its clarity and hardness. Its chemical formula is Al2SiO4(OH,F)2.
Here's a comparative table summarizing key properties:
| Gemstone | Chemical Formula | Hardness (Mohs) | Key Characteristics |
|---|---|---|---|
| Turquoise | CuAl6(PO4)4(OH)8·4H2O | 5-6 | Opaque, hydrated phosphate of copper and aluminum |
| Blue Zircon | ZrSiO4 | 6.5-7.5 | High refractive index, brilliance |
| Tanzanite | Ca2Al3(SiO4)3(OH) | 6-7 | Pleochroism, vivid blue to purple hues |
| Blue Topaz | Al2SiO4(OH,F)2 | 8 | Clarity, hardness |
Symbolism and Metaphysical Beliefs
Throughout history, each of these gemstones has been attributed with specific meanings and powers. Turquoise has long been revered for its spiritual and healing qualities, particularly in ancient cultures. In India, it is the birthstone for Sagittarius and is believed to promote good health. Traditionally, Hindu jewelers set birthstones in a way that ensures direct contact with the skin to maximize their benefits.
Blue Zircon is associated with prosperity and wisdom. While less prominent in modern metaphysical beliefs, it was historically valued for its perceived protective qualities.
Tanzanite, being a more recent discovery, has developed symbolism linked to transformation, intuition, and spiritual awareness. Its vibrant color is often associated with royalty and elegance.
Blue Topaz is often linked to communication, loyalty, and clarity of thought. It is believed to promote a sense of calm and tranquility.
Care and Cleaning
The care required for each gemstone varies based on its hardness and other properties. Turquoise, being relatively soft, is susceptible to scratches and should be protected from harsh chemicals and impacts. Cleaning should be done gently with a soft cloth and mild soap.
Blue Zircon, with its good hardness, is more durable but can still be chipped with a sharp blow. It can be cleaned with warm, soapy water and a soft brush.
Tanzanite is also relatively durable but can be damaged by sudden temperature changes. It should be cleaned with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners.
Blue Topaz, being quite hard, is relatively resistant to scratches. It can be cleaned with warm, soapy water and a soft brush, or with an ultrasonic cleaner.
Conclusion
The December birthstones – Tanzanite, Turquoise, Blue Zircon, and Blue Topaz – represent a captivating spectrum of blue hues and a rich tapestry of history, geological origins, and symbolic meanings. From the ancient traditions surrounding Turquoise to the modern allure of Tanzanite, each gem offers a unique connection to the final month of the year. Whether chosen for their aesthetic beauty, perceived metaphysical properties, or historical significance, these stones provide a meaningful way for December-born individuals to express their identity and celebrate their birth month.