December, the final month of the year, is distinguished in the world of gemology for its unique distinction of having four official birthstones: turquoise, tanzanite, blue zircon, and blue topaz. These gemstones, all sharing the cool, soothing tones of blue, reflect the wintertime palette and carry with them a rich tapestry of history, symbolism, and geological significance. While some months are associated with a single birthstone, December stands out with multiple options—each offering its own allure, meaning, and practicality for jewelry design.
This article delves into the characteristics, origins, symbolism, and care of the four December birthstones, drawing on historical and modern sources. Each stone has its own story, from ancient cultural reverence to modern commercial significance, and together they form a remarkable collection that continues to captivate gemstone lovers and collectors alike.
History and Lore of December Birthstones
The tradition of associating gemstones with specific months can be traced back centuries, with roots in biblical and ancient cultural traditions. While the exact origins of the December birthstone tradition remain unclear, the concept has evolved significantly over time, particularly in the United States, where the selection of gemstones has been standardized and updated.
The Evolution of December’s Birthstones
In 1912, the National Association of Jewelers (now the Jewelers of America) played a key role in standardizing the list of American birthstones, aligning traditional beliefs with commercially viable gemstones that could be marketed effectively. This list was updated again in 1952, adding blue zircon to the December lineup. A further addition came in 2002, when tanzanite was officially recognized as a December birthstone due to its striking blue color and increasing popularity.
Today, the four officially recognized December birthstones are:
- Turquoise
- Tanzanite
- Blue Zircon
- Blue Topaz
The addition of multiple stones to December’s list is thought to have been a practical decision by the jewelry industry, allowing for a wider range of affordable and visually appealing options. This expansion also reflects the dynamic nature of gemstone markets, where new discoveries and treatments can influence the popularity and availability of certain stones.
Cultural and Historical Significance
Among these four, turquoise holds the longest and most storied history. Revered by ancient civilizations including the Egyptians, Persians, and Native Americans, turquoise was believed to possess protective and healing properties. Its use in jewelry and ceremonial artifacts dates back thousands of years, with King Tutankhamun's tomb containing turquoise-adorned items. The gemstone was often associated with wisdom, tranquility, and friendship.
Tanzanite, in contrast, is a relatively modern discovery. First identified in Tanzania in the 1960s, it was not officially recognized as a birthstone until 2002. Its deep blue to violet hues, enhanced through heat treatment, quickly made it a popular choice for fine jewelry. The rarity of tanzanite—being found only in a specific region of Tanzania—also contributes to its allure.
Blue zircon and blue topaz, while both blue-hued, differ significantly in their geological origins and properties. Blue topaz, in particular, has become a favored choice for its durability and affordability, making it a practical option for everyday wear. Blue zircon, on the other hand, is often used as an affordable alternative to more expensive blue gemstones like sapphire.
Geological Formation and Sources
Each of the four December birthstones has a distinct geological origin and is found in specific parts of the world. Understanding where these gemstones are formed and mined helps to appreciate their rarity, beauty, and availability.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, formed through a complex process involving groundwater. The formation of turquoise typically occurs in arid regions where copper-rich bedrock is exposed to weathering. Over time, water carrying copper and other minerals seeps through the rock, reacting with phosphate to create the distinctive blue and green hues of turquoise. The presence of iron and other trace elements often results in the dark matrix lines that many turquoise stones display.
The most historically significant source of turquoise is Iran, where it has been mined for thousands of years. The Persian turquoise found in these mines is highly prized for its intense blue color and minimal matrix. Another notable source is the United States, particularly in Arizona, where the Sleeping Beauty Mine was once a major producer of high-quality turquoise. This mine, which closed in 2015, was known for its pure, robin’s-egg blue color and was a favorite among jewelers and collectors.
Other significant sources of turquoise include Egypt, Mexico, China, and parts of Central Asia and Africa. The availability of turquoise from these regions contributes to its continued presence in the jewelry market.
Tanzanite
Tanzanite is a variety of the mineral zoisite, and its blue to violet color is the result of trace amounts of vanadium. Unlike most gemstones, tanzanite is only found in one location on Earth: a specific area of the Merelani Hills in Tanzania, near the border with Kenya. The gemstone was first discovered in the 1960s and was named after the country of its origin. It quickly became popular due to its striking color and the fact that it was a new discovery in a time of increasing interest in exotic gemstones.
The Merelani deposits are the only known source of tanzanite, making it one of the rarest gemstones in the world. The gem is often found in a rough, unprocessed state and must be heat-treated to enhance its color. This treatment removes the gray and green hues, revealing the deep blue and violet tones that make tanzanite so desirable.
Blue Zircon
Zircon is a silicate mineral that occurs in a range of colors, including blue, yellow, green, and red. The blue color in zircon is achieved through a process of heat treatment, which stabilizes the stone and enhances its color. Blue zircon is a popular alternative to sapphire and other blue gemstones due to its affordability and vibrant color.
Blue zircon is found in several parts of the world, including Brazil, Cambodia, and parts of the United States. It is often used in fashion jewelry and is favored for its brilliance and clarity.
Blue Topaz
Blue topaz is a variety of the mineral topaz that has been treated to achieve its blue color. Natural blue topaz is extremely rare, so most blue topaz available on the market has been irradiated and heat-treated to create the desired blue hues. The treatment is stable and does not affect the durability or value of the gemstone.
Blue topaz is found in various parts of the world, including Brazil, Mexico, Nigeria, and the United States, particularly in Texas, where it is the official state gem. It is known for its high hardness on the Mohs scale, making it one of the most durable December birthstones.
Gemological Properties
Each December birthstone has distinct gemological properties that influence its use in jewelry, its durability, and its value. Below is a comparison of the key characteristics of each gemstone:
| Gemstone | Chemical Formula | Hardness (Mohs) | Color | Refractive Index | Luster | Transparency |
|---|---|---|---|---|---|---|
| Turquoise | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5–6 | Blue, green | 1.61–1.65 | Waxy to greasy | Opaque to slightly translucent |
| Tanzanite | Ca₂Al₃(PO₄)₃(OH)₃·H₂O | 6–7 | Blue to violet | 1.69–1.70 | Vitreous | Transparent |
| Blue Zircon | ZrSiO₄ | 6–7.5 | Blue, yellow | 1.92–2.00 | Vitreous | Transparent to translucent |
| Blue Topaz | Al₂SiO₄(F,OH)₂ | 8 | Blue | 1.62–1.64 | Vitreous | Transparent |
Turquoise
Turquoise is relatively soft compared to other gemstones, with a hardness of 5–6 on the Mohs scale. Its waxy to greasy luster and opaque to slightly translucent nature make it distinct from other blue gemstones. The presence of matrix lines (the dark, web-like patterns) is a defining characteristic of turquoise and is often considered a desirable feature in certain designs.
Tanzanite
Tanzanite has a hardness of 6–7, making it more durable than turquoise but still less so than blue topaz. It has a vitreous luster and is typically transparent. One unique property of tanzanite is its pleochroism—the ability to display different colors when viewed from different angles. Tanzanite can appear blue, purple, or even brown depending on the angle of light and the observer's position.
Blue Zircon
Blue zircon is relatively hard, with a hardness of 6–7.5, and has a high refractive index, which gives it a brilliant, glassy luster. It is often compared to sapphire due to its similar color and clarity, though it is more affordable and less durable. Blue zircon is commonly used in fashion jewelry and is favored for its affordability and vibrant color.
Blue Topaz
Blue topaz is the hardest of the four December birthstones, with a hardness of 8 on the Mohs scale. This makes it ideal for everyday wear and suitable for use in rings, bracelets, and other frequently worn jewelry. It has a vitreous luster and is transparent, allowing light to pass through easily and creating a bright, sparkly appearance.
Symbolism and Metaphysical Beliefs
Each of the four December birthstones carries its own set of symbolic meanings and metaphysical properties, which have been passed down through centuries of cultural and spiritual traditions.
Turquoise
Turquoise has long been associated with protection, wisdom, and good fortune. In ancient times, it was believed to ward off negative energy and to bring the wearer strength and clarity. Native American tribes, for example, used turquoise in ceremonies and as a symbol of health and prosperity. In Persian culture, it was considered a stone of divine wisdom and was often worn by scholars and spiritual leaders.
Modern metaphysical beliefs associate turquoise with emotional balance, communication, and mental clarity. It is often used in meditation and is said to promote a sense of calm and tranquility.
Tanzanite
Tanzanite is relatively new in the world of metaphysical gemstones, but it has quickly become associated with emotional healing and spiritual transformation. It is believed to help the wearer release old patterns and emotions, making it a stone of personal growth and self-discovery. Tanzanite is also thought to enhance intuition and psychic awareness.
Blue Zircon
Blue zircon is associated with clarity of thought, emotional stability, and spiritual awakening. It is believed to help the wearer overcome fear and anxiety and to bring a sense of peace and harmony. Some traditions suggest that blue zircon can enhance one’s ability to manifest goals and to attract positive energy.
Blue Topaz
Blue topaz is often associated with calmness, wisdom, and protection. It is believed to help the wearer manage stress and to promote a sense of inner peace. Blue topaz is also linked to the throat chakra and is thought to enhance communication and self-expression.
Care and Cleaning
Proper care and cleaning are essential for preserving the beauty and longevity of any gemstone. The four December birthstones have different care requirements due to their varying hardness and sensitivity to certain substances.
Turquoise
Turquoise is relatively soft and porous, making it susceptible to damage from heat, water, and chemicals. It should be cleaned gently with a soft cloth and mild soap. Avoid using ultrasonic or steam cleaners, as these can cause the stone to lose its color or become damaged. Turquoise should also be stored separately from other gemstones to prevent scratches.
Tanzanite
Tanzanite is sensitive to high heat and should not be exposed to temperatures above 300°F. It can be cleaned with a soft cloth and mild soap, but ultrasonic and steam cleaning should be avoided unless done by a professional. Tanzanite should also be kept away from harsh chemicals and should not be worn during activities that may cause physical impact.
Blue Zircon
Blue zircon is relatively durable but should still be handled with care. It can be cleaned with a soft cloth and mild soap, but ultrasonic and steam cleaning should be avoided as they can potentially damage the stone. Blue zircon should be stored separately to avoid scratches from harder gemstones.
Blue Topaz
Blue topaz is the hardest of the four December birthstones and is generally easy to care for. It can be cleaned with a soft cloth and mild soap or with an ultrasonic cleaner. It is resistant to most chemicals and can be worn during most daily activities. However, it should be kept away from high heat and strong acids.
Conclusion
December is a month rich in gemstone lore and significance, offering a unique collection of four officially recognized birthstones: turquoise, tanzanite, blue zircon, and blue topaz. Each of these gemstones brings its own charm, history, and symbolism, making them a valuable addition to any jewelry collection.
Turquoise, with its ancient heritage and protective qualities, has been cherished for thousands of years. Tanzanite, a modern discovery, has quickly become a favorite among gemstone enthusiasts for its rarity and vibrant color. Blue zircon and blue topaz offer more affordable and durable options, with blue topaz standing out for its exceptional hardness and brilliance.
Whether you are drawn to the deep blue of tanzanite, the warm blue-green tones of turquoise, or the bright blue of topaz, there is a December birthstone to suit every taste and occasion. Understanding the history, properties, and symbolism of these gemstones not only enhances their beauty but also deepens one's appreciation for their enduring significance in the world of gemology.
Sources
- December Birthstone: Blue Zircon, Blue Topaz, Tanzanite, and Turquoise
- December Birthstones: Turquoise, Tanzanite, Blue Zircon, and Blue Topaz
- Meet All Four December Birthstones
- December Birthstones Meaning and History
- Gem Society's Guide to December Birthstones
- December Birthstones and Their Symbolism