December boasts a remarkable selection of birthstones – blue topaz, blue zircon, tanzanite, and turquoise – offering a spectrum of blues to suit every preference. While tanzanite is included as a December birthstone, the most historically significant and frequently referenced gems are blue topaz, turquoise, and zircon. This article will delve into the history, geological origins, gemological properties, and cultural significance of these three captivating gemstones, providing a comprehensive overview for enthusiasts and those seeking to understand the rich heritage of December’s birthstones.
A History Rooted in Antiquity
The history of December’s birthstones stretches back millennia. Turquoise, arguably the oldest of the three, holds a particularly venerable position. Archaeological evidence suggests its use as far back as 7000 BCE, with discoveries in burial sites in western Iran. Ancient Egyptians revered turquoise, associating it with good luck, fertility, and the goddess Hathor, incorporating it into amulets, beads, and other ornamental objects. This tradition continued for centuries, with turquoise appearing in the funerary mask of King Tut, demonstrating its enduring importance in ancient Egyptian culture. Ancient China also valued turquoise, carving it over 3,000 years ago. In European traditions, the gifting of a turquoise ring symbolized a promise of remembrance – “forget me not.” Tibetan culture considers turquoise a national treasure, believing it grants health, good fortune, and protection from evil.
Zircon also possesses a long and storied past. Its name originates from the Arabic words zar (gold) and gun (color), reflecting its early appearance in golden-hued varieties. Throughout history, zircon was believed to possess protective qualities, capable of relieving pain, increasing appetite, and safeguarding travelers from injury and disease. It was also thought to ensure peaceful sleep and welcome visitors.
Blue topaz, while a popular modern choice, has a comparatively shorter documented history as a birthstone. The name "topaz" itself derives from the Sanskrit word for "fire," hinting at the gem’s inherent brilliance. However, the widespread use of blue topaz as a December birthstone is largely a result of modern gemological practices, specifically the irradiation of naturally colorless topaz to achieve the desired hue.
Geological Formation and Global Sources
The formation of these three gemstones occurs through vastly different geological processes and in geographically diverse locations. Turquoise, a hydrated phosphate of copper and aluminum, forms through chemical reactions in the presence of copper-rich solutions percolating through volcanic rock. Historically, Iran’s Nishapur district was prized for its intensely blue turquoise, often referred to as “robin’s egg blue” or “Persian blue.” While Iran remains a significant source, the United States, particularly Arizona and Nevada, currently leads in turquoise production. Mines in these states, such as the Kingman and now-closed Sleeping Beauty mines in Arizona, are known for their high-quality turquoise. More recently, China’s Hubei Province has become a major producer of gem-quality turquoise.
Zircon forms in igneous rocks, often as a byproduct of magma crystallization. It is found in a variety of colors, with blue being achieved through heat treatment. Zircon deposits are located in several countries, including Thailand, Cambodia, Vietnam, Nigeria, and Australia.
Blue topaz, as a variety of topaz, crystallizes from fluorine-rich volcanic or pegmatitic rocks. While natural blue topaz exists, it is exceptionally rare. The vast majority of commercially available blue topaz is created by irradiating colorless topaz, which is commonly found in Brazil, Nigeria, and Russia.
Gemological Properties: A Comparative Overview
Each of these December birthstones possesses unique gemological properties that contribute to its distinct appeal.
Turquoise is a semi-translucent to opaque gem with a Mohs hardness ranging from 5 to 6, making it relatively soft and susceptible to scratching. Its chemical composition is CuAl6(PO4)4(OH)8·4H2O. The presence of matrix – remnants of the host rock – often creates distinctive veining patterns within the stone. Turquoise can be treated to enhance its durability and appearance, including dyeing and stabilization with epoxy or acrylic resin.
Zircon exhibits a higher Mohs hardness of 6.5 to 7.5, making it more durable than turquoise. Its chemical formula is ZrSiO4. While commonly associated with blue hues, zircon naturally occurs in a wide range of colors. Blue zircon is often created through heat treatment of brownish zircon.
Blue Topaz boasts a Mohs hardness of 8, making it a relatively hard and durable gemstone. Its chemical formula is Al2SiO4(F,OH)4. Blue topaz varieties, such as London Blue, Swiss Blue, and Sky Blue, are distinguished by the intensity and shade of their color, typically achieved through irradiation. It exhibits strong chemical bonding, classifying it as harder than most silicate minerals.
The following table summarizes key gemological properties:
| Property | Turquoise | Zircon | Blue Topaz |
|---|---|---|---|
| Mohs Hardness | 5-6 | 6.5-7.5 | 8 |
| Chemical Formula | CuAl6(PO4)4(OH)8·4H2O | ZrSiO4 | Al2SiO4(F,OH)4 |
| Transparency | Semi-translucent to Opaque | Transparent to Opaque | Transparent |
| Common Colors | Blue to Green | Various, often Blue | Shades of Blue |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been imbued with symbolic meaning and metaphysical properties. Turquoise, as previously mentioned, was associated with good fortune, protection, and health in numerous cultures. It was believed to safeguard against falls and ward off disaster.
Zircon was thought to bestow power, relieve pain, and protect travelers. It was also believed to promote restful sleep and attract positive energy.
While blue topaz doesn’t have the same extensive historical lore as turquoise and zircon, it is often associated with communication, loyalty, and emotional stability. Its calming blue color is believed to promote tranquility and reduce stress.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these December birthstones. Turquoise, due to its relative softness, requires gentle handling and should be protected from scratches and impacts. It should be cleaned with warm, soapy water and never subjected to steam or ultrasonic cleaners, as these can damage treated surfaces. Turquoise is also sensitive to acids, chemicals, cosmetics, and even skin oils.
Zircon, with its greater hardness, is more durable but still requires care. Avoid harsh chemicals and ultrasonic cleaners. Gentle cleaning with warm, soapy water is recommended.
Blue topaz, being the hardest of the three, is relatively resistant to scratching. However, it should still be protected from impacts and extreme temperature changes. Cleaning can be performed with warm, soapy water or a commercial jewelry cleaner.
Conclusion
Blue topaz, turquoise, and zircon represent a diverse and captivating collection of December birthstones. From the ancient origins of turquoise and zircon to the modern appeal of irradiated blue topaz, these gemstones offer a rich tapestry of history, geological wonder, and cultural significance. Each stone possesses unique properties and symbolism, making them cherished adornments and meaningful gifts for those born in the final month of the year. Their enduring beauty and captivating lore ensure their continued prominence in the world of gemstones.