December is unique among the months in the calendar year as it boasts not one, but three or even four officially recognized birthstones: turquoise, zircon (specifically blue zircon), tanzanite, and—depending on the source—blue topaz. This multiplicity is the result of historical evolution, cultural influence, and the desire to offer a range of options that vary in cost, availability, and aesthetic appeal. Each of these gemstones carries with it a rich tapestry of geological, historical, and symbolic significance. This article explores the history, properties, symbolism, and care of these December birthstones, drawing on the most reliable and corroborated information from the provided sources.
Introduction
The tradition of birthstones—assigning a particular gemstone to each month of the year—has ancient roots, with the earliest known references dating back to the Bible. Over time, this tradition has evolved, influenced by cultural shifts, scientific discoveries, and commercial interests. December, in particular, has undergone significant changes in its list of birthstones. What was once assigned ruby in some ancient traditions now includes turquoise, zircon, tanzanite, and in some contemporary sources, even blue topaz.
This article delves into the origins and evolution of these gemstones as December birthstones, examining their geological properties, their cultural and historical contexts, and the symbolic meanings they carry. It also offers guidance on how to care for these stones, given their varying hardness and sensitivity to environmental factors.
Historical and Cultural Significance
The concept of assigning gemstones to months of the year is ancient, with one of the earliest known references appearing in the Breastplate of Aaron described in the Book of Exodus in the Hebrew Bible. This list included 12 stones, one for each tribe of Israel, and was later interpreted in various ways by different cultures and periods. However, the modern birthstone tradition as we know it today was formalized much later.
The earliest known reference to turquoise as a December birthstone comes from a pamphlet titled Gregorian Birthstone Poems, published by Tiffany & Co. in 1870. This marked the beginning of a long and evolving tradition that would see the list of December's birthstones expand over the decades.
In 1912, the National Association of Jewellers (now the Jewelers of America) listed turquoise as the primary December birthstone and lapis lazuli as an alternative. Then, in 1952, zircon—specifically blue zircon—was added by the Jewelry Industry Council of America. Finally, in 2002, tanzanite was officially added, further expanding the list.
Some sources, like the Gems Society article, also include blue topaz as a December birthstone, making it a four-stone month. This variation highlights the fluid nature of the birthstone tradition, shaped by both historical precedent and modern commercial interests.
The inclusion of multiple stones for December is often attributed to the desire to provide more affordable alternatives to the traditional, and often more expensive, stones. This is particularly relevant for turquoise, which, while historically significant, is a relatively soft and porous stone that requires careful handling.
Geological Formation and Sources
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It is formed through a complex geological process involving the interaction of copper-rich solutions with aluminum- and phosphorus-bearing rocks. This typically occurs in arid regions where water percolates through copper deposits and reacts with surrounding minerals to form turquoise in cavities and fractures in the rock.
The primary sources of turquoise include the United States (especially Nevada and Arizona), China, Egypt, Iran, and Mexico. The stone is often found in weathered volcanic and sedimentary rocks, particularly in areas with a history of copper mining.
Turquoise is relatively soft, with a hardness of 5 to 6 on the Mohs scale. It is also porous and can be easily damaged by exposure to oils, acids, and excessive light. These properties make it less suitable for rings and other jewelry that is subject to daily wear.
Zircon
Zircon is a silicate mineral with the chemical formula ZrSiO₄. It is known for its high refractive index and dispersion, which can give it a diamond-like sparkle. Zircon occurs in various colors, but the blue variety—known as blue zircon—is the one most commonly associated with December.
Blue zircon is typically created through heat treatment of brown or yellow zircon. This process stabilizes the color and enhances its brilliance. Zircon is found in many parts of the world, including Australia, Brazil, Cambodia, and Thailand. It has a hardness of 6.5 to 7.5 on the Mohs scale, making it more durable than turquoise but still somewhat sensitive to impact.
Tanzanite
Tanzanite is a relatively recent addition to the birthstone list, discovered in 1967 in Tanzania. It is a variety of the mineral zoisite, with the chemical formula Ca₂Al₃(SiO₄)(OH)₃(OH). Tanzanite is notable for its trichroism, meaning it can display three different colors—blue, purple, and brown—depending on the angle of light.
As the name suggests, tanzanite is found exclusively in Tanzania, specifically in the area near Mount Kilimanjaro. It is a relatively soft stone, with a hardness of 6 to 6.5 on the Mohs scale. Tanzanite is also sensitive to heat and can fade or lose its color if exposed to high temperatures or prolonged sunlight.
Gemological Properties
| Gemstone | Color | Hardness (Mohs Scale) | Chemical Formula | Origin | Durability |
|---|---|---|---|---|---|
| Turquoise | Blue to green | 5–6 | CuAl₆(PO₄)₄(OH)₈·4H₂O | USA, Mexico, Egypt, Iran | Low |
| Zircon | Blue, yellow, brown | 6.5–7.5 | ZrSiO₄ | Australia, Thailand, Brazil | Moderate |
| Tanzanite | Blue-violet | 6–6.5 | Ca₂Al₃(SiO₄)(OH)₃(OH) | Tanzania | Low to Moderate |
| Blue Topaz (implied in some sources) | Blue | 8 | Al₂SiO₆ | Brazil, USA, Nigeria | High |
Turquoise
Turquoise is known for its distinctive blue-to-green coloration, often with a mottled or marbled appearance due to the presence of other minerals. Its hardness of 5–6 makes it relatively soft compared to other gemstones, and it is easily scratched or fractured. It is also porous and can absorb oils, lotions, and other substances that may alter its color.
Turquoise is best suited for jewelry that is worn infrequently or with care, such as pendants, earrings, or brooches. Its softness and porosity also make it ideal for inlay work, where it is embedded into harder materials like silver or wood.
Zircon
Zircon is a versatile gemstone that occurs in a range of colors, including red, yellow, green, and blue. The blue zircon most commonly associated with December is typically heat-treated to achieve its vibrant color. It has a higher refractive index than many other gemstones, which gives it a bright, sparkly appearance.
With a hardness of 6.5–7.5, zircon is more durable than turquoise but still requires careful handling. It is not recommended for rings or other jewelry that may be subject to frequent impact or abrasion.
Tanzanite
Tanzanite is prized for its deep blue-violet color and its trichroic nature. It is a relatively soft stone, with a hardness of 6–6.5, and is sensitive to heat and light. Tanzanite is also pleochroic, meaning it can display different colors under different lighting conditions.
Due to its softness and sensitivity, tanzanite is best suited for jewelry that is worn with care. It is often used in pendants, earrings, and brooches rather than in rings or bracelets.
Symbolism and Metaphysical Beliefs
Turquoise
Turquoise has been used for thousands of years as a protective stone. Ancient civilizations such as the Egyptians, Persians, and Native Americans all valued turquoise for its protective and healing properties. It was often used in amulets and talismans to ward off illness, bring good fortune, and ensure safe travel.
In Native American cultures, turquoise was considered a sacred stone, associated with the sky and water. It was often used in ceremonies and as a symbol of wisdom and spiritual protection.
In modern metaphysical traditions, turquoise is believed to promote emotional balance, calmness, and communication. It is also associated with throat chakra activation and is thought to enhance self-expression and truthfulness.
Zircon
Zircon is often referred to as the "gem of the stars" due to its brilliance and sparkle. It has long been associated with fire and light. In some cultures, zircon was believed to bring good fortune and protect against illness.
Blue zircon, in particular, is thought to promote mental clarity and emotional stability. It is also believed to enhance spiritual awareness and intuition.
Tanzanite
Tanzanite is a relatively modern discovery in the world of gemstones, but it quickly gained popularity for its deep blue-violet color and its association with transformation and healing. It is believed to help with emotional healing, self-awareness, and spiritual growth.
In chakra work, tanzanite is associated with the throat, third eye, and crown chakras. It is thought to help open communication with higher dimensions and enhance psychic abilities.
Care and Cleaning
Proper care is essential for preserving the beauty and longevity of December birthstones, especially given their varying degrees of hardness and sensitivity.
Turquoise
Turquoise requires careful handling due to its softness and porosity. It should be protected from oils, lotions, and perfumes, as these can discolor the stone. It should also be kept away from direct sunlight and heat, which can cause it to dry out and change color.
Cleaning turquoise should be done gently. A soft cloth and a mild soap solution are recommended. Ultrasonic and steam cleaners should be avoided, as they can damage the stone.
Zircon
Zircon is more durable than turquoise but still requires gentle care. It should be cleaned with warm, soapy water and a soft cloth. Avoid harsh chemicals and ultrasonic cleaners, especially for heat-treated zircons, as these can affect the color.
Zircon should also be stored separately from harder gemstones to prevent scratches.
Tanzanite
Tanzanite is sensitive to both heat and light. Prolonged exposure to sunlight can cause it to fade or lose its color. It should be stored in a dark, cool place when not in use.
Cleaning tanzanite should be done with warm water and a mild detergent. Avoid using ultrasonic or steam cleaners, as these can damage the stone.
Conclusion
December birthstones—turquoise, zircon, tanzanite, and in some sources, blue topaz—offer a rich and diverse selection of gemstones that reflect the month's wintry charm and festive spirit. Each of these stones has its own unique geological properties, historical significance, and symbolic meaning, making them not only beautiful but also meaningful choices for jewelry and personal adornment.
Turquoise, with its ancient roots and protective properties, has been a favorite for millennia. Zircon, with its brilliant sparkle and affordability, adds a touch of elegance and versatility. Tanzanite, a modern discovery, brings a sense of rarity and transformation. Together, these gemstones represent the evolving nature of the birthstone tradition, shaped by history, culture, and commerce.
Whether chosen for their beauty, their meaning, or their rarity, December's birthstones continue to captivate and inspire, offering a timeless connection to the past and a meaningful gift for the future.