December is unique in the world of birthstones, holding the distinction of having the most gemstone options associated with a single month. This abundance offers a diverse palette of blue hues, mirroring the cool, crisp imagery of winter. The four widely recognized December birthstones—Turquoise, Zircon, Tanzanite, and Blue Topaz—each possess distinct histories, geological origins, and symbolic meanings. While some, like Turquoise, have been revered for millennia, others, such as Tanzanite, are celebrated modern discoveries. Understanding the characteristics of each gem allows enthusiasts, collectors, and jewelry buyers to make informed choices based on personal preference, durability, and value. This article explores the rich tapestry of these four blue gems, detailing their historical significance, geological formation, gemological properties, and care requirements, drawing exclusively from the provided source materials.
History and Lore
The tradition of birthstones is deeply rooted in history, with many lists tracing their origins to the biblical descriptions of Aaron's breastplate or the foundation gems of the New Jerusalem. The modern standardized list, however, is a more recent development. In 1912, the National Association of Jewelers in the United States formalized an unofficial list, blending ancient customs with gemstones deemed practical for the jewelry trade. This list has evolved over time. In 1952, the Jewelry Industry Council of America added Zircon to December’s offerings, and in 2002, the American Gem Trade Association (AGTA) introduced Tanzanite, cementing December’s status as the month with the most birthstones. The reason for this expansion is not definitively known, but it is believed to have been driven by a desire to offer consumers more affordable and varied options as new gemstones entered the market.
Turquoise is arguably the oldest of the December gems, with a history spanning thousands of years. Its name derives from its journey through Turkish gem markets, where it was transported from its origins in Persia and the Sinai Peninsula. Ancient civilizations prized Turquoise for its protective qualities; it was frequently carved into amulets and inscribed with symbols to ward off danger and bring good fortune. It was a gem of love and marriage, believed to preserve relationships and friendships when gifted. The stone was also thought to be a health monitor, changing color to warn its wearer of impending illness. This belief was shared across cultures, from the ancient Incas and Mayas, who offered it to their gods, to the Tibetans, who valued it as a symbol of fortune, health, and success and even used it as currency. In the American Southwest, Native American tribes associated Turquoise with youth and strength.
Zircon has a more complex history, often confused with the man-made cubic zirconia. In its natural form, Zircon is one of the oldest minerals on Earth, but its use as a birthstone is more recent. It was added to the official list in 1952 to provide an alternative that offered exceptional brilliance and fire. Historically, blue Zircon was a popular gem in the Victorian era, valued for its diamond-like appearance and clarity.
Tanzanite is the newest member of the December family, a 20th-century discovery. It was introduced to the global market in the late 1960s and was officially added as a birthstone in 2002. Its rapid acceptance into the birthstone canon is a testament to its stunning beauty and unique origin story, which adds a modern chapter to the ancient tradition of birthstones.
Blue Topaz, while not part of the traditional December list, has gained significant popularity and is now widely recognized as a modern alternative. Its historical origins are somewhat vague, with evidence of its use found throughout history, but it was the commercial appeal and durability that led to its inclusion in the contemporary market. It serves as an accessible and durable option for those seeking a crisp, wintry blue gem.
Geological Formation and Sources
The four December birthstones are formed under vastly different geological conditions and are sourced from distinct regions of the world, contributing to their rarity and value.
Turquoise is a secondary mineral formed in arid regions where acidic, copper-rich water percolates through rocks containing aluminum and phosphorus. It is typically found in veins or nodules within host rock. Historically, significant sources included Persia (modern-day Iran) and the Sinai Peninsula. Today, while turquoise is mined in various locations, its most prized varieties come from the American Southwest, particularly Arizona and New Mexico, as well as from China and Egypt.
Zircon is a primary mineral that crystallizes from magma. It is commonly found in granite and metamorphic rocks. The blue variety, which is most associated with December, is often found in Sri Lanka, Thailand, and Cambodia. Its hardness and durability make it a resilient gem, though it can be brittle.
Tanzanite is exceptionally rare, as it is found in only one location on Earth: the Merelani Hills of northern Tanzania. This geographic exclusivity is a primary driver of its value. The gem forms through a unique geological process involving the metamorphism of specific rocks under intense heat and pressure, a process that is believed to have occurred roughly 585 million years ago. Its limited source makes it one of the rarest gemstones in the world.
Blue Topaz is a silicate mineral that forms in igneous rocks, particularly in pegmatites and hydrothermal veins. It is mined in several countries, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States. Notably, Blue Topaz is the official state gem of Texas, reflecting its significance in American gemology. The vibrant blue color of most commercial Blue Topaz is achieved through irradiation and heat treatment of colorless or pale yellow topaz, a standard and stable industry practice.
Gemological Properties
Understanding the physical and chemical properties of these gems is essential for appreciating their beauty and ensuring their proper care. The following table summarizes key gemological data for the December birthstones based on the provided sources.
| Gemstone | Chemical Composition | Mohs Hardness | Typical Color | Notable Characteristics |
|---|---|---|---|---|
| Turquoise | Hydrated copper aluminum phosphate | 5 - 6 | Sky blue to greenish-blue | Often exhibits a matrix (webbing) from host rock; porous and can be dyed or stabilized. |
| Zircon | Zirconium silicate (ZrSiO₄) | 6.5 - 7.5 | Bright, clear blue (after treatment) | High refractive index and dispersion, giving it exceptional brilliance and fire; can be brittle. |
| Tanzanite | Calcium aluminum silicate hydroxide | 6.5 - 7 | Rich violet-blue (pleochroic) | Exhibits strong pleochroism, showing blue, violet, and burgundy hues from different angles. |
| Blue Topaz | Aluminum silicate fluoride hydroxide | 8 | Crisp, sky blue to deep blue | The hardest of the December birthstones, making it excellent for everyday wear. |
Turquoise is relatively soft and porous. Its color can range from a light sky blue to a greenish hue, often influenced by the presence of iron. The stone frequently contains a dark, spiderweb-like pattern known as matrix, which is part of the host rock. Due to its porosity, Turquoise is often stabilized with resins or waxes to enhance its durability and color.
Zircon is renowned for its exceptional optical properties. It has a high refractive index and significant dispersion, which is the ability to split white light into spectral colors, resulting in a sparkle that rivals diamond. While naturally occurring blue zircon exists, much of the vibrant blue material on the market is heat-treated from brownish zircon. It is important to handle zircon with care, as it can be brittle and prone to chipping if struck.
Tanzanite is prized for its strong pleochroism. This means that when viewed from different crystallographic directions, it displays different colors—typically blue, violet, and a reddish-brown. Gem cutters must orient the stone carefully to present the desired blue-violet hue. Its hardness is moderate, making it less suitable for rough daily wear without proper protection.
Blue Topaz stands out for its durability. With a Mohs hardness of 8, it is the hardest and most resilient of the four December birthstones, making it an excellent choice for rings and other jewelry that may be subject to daily wear. The deep, saturated blue of many commercial Blue Topaz gems is a result of a stable treatment process, making this beautiful color accessible at a relatively affordable price point.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, each December birthstone carries a legacy of symbolic meaning and metaphysical belief, often rooted in ancient traditions.
Turquoise is universally regarded as a stone of protection, grounding, and good fortune. It is believed to bring calm and stability, shielding the wearer from negative energies and harm. In relationships, it is a symbol of fidelity and enduring friendship, making it a meaningful gift. Its association with health is ancient, with beliefs that it could warn of danger or illness by changing color.
Zircon is associated with mental clarity, wisdom, and balance. It is thought to sharpen focus and aid in clear thinking, making it a stone for scholars and those seeking knowledge. Its brilliant sparkle is also linked to spiritual illumination and a sense of order.
Tanzanite, as a modern gem, has been attributed meanings of transformation, new beginnings, and spiritual awakening. Its unique color shift is seen as a metaphor for moving through change with clarity and curiosity. It is a stone for those embarking on new chapters in life, encouraging a forward-looking perspective.
Blue Topaz, with its serene, icy blue hue, is often linked to communication, calm, and peace. It is believed to soothe the mind and encourage honest expression. Its durability can be seen as a metaphor for steadfastness and resilience.
Care and Cleaning
Proper care is crucial to maintaining the beauty and longevity of any gemstone jewelry. The varying hardness and stability of the December birthstones necessitate specific cleaning and handling guidelines.
Turquoise requires the most careful handling. Its relative softness and porosity make it susceptible to scratching, cracking, and damage from chemicals. Clean it with a soft, dry cloth; avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. It should be stored separately from harder gems to prevent scratches.
Zircon, while harder than Turquoise, is brittle. It can withstand standard cleaning methods, but avoid sudden temperature changes and hard blows. A soft brush with mild soap and warm water is sufficient for cleaning. Due to its brittleness, it is best set in protective settings like bezels for rings.
Tanzanite should be handled with care due to its moderate hardness and perfect cleavage in one direction, which makes it vulnerable to breakage. It is not recommended for rings worn daily. Clean it with a soft brush, mild soap, and lukewarm water. Avoid ultrasonic cleaners and extreme temperature changes, which can cause damage.
Blue Topaz, being the hardest of the group, is the most durable and easiest to care for. It can be cleaned with a standard jewelry cleaning solution, a soft brush, and warm water. It is also safe for ultrasonic cleaners, making it a practical choice for active lifestyles. However, like all colored gemstones, it should be protected from sharp blows and abrasive surfaces.
Conclusion
The four December birthstones—Turquoise, Zircon, Tanzanite, and Blue Topaz—offer a remarkable range of options for those born in the final month of the year. From the ancient, protective legacy of Turquoise to the brilliant, diamond-like sparkle of Zircon, the modern rarity of Tanzanite, and the durable, serene beauty of Blue Topaz, each gem tells a unique story. Their shared theme of blue hues captures the essence of winter, but their individual histories, origins, and properties provide a wealth of choice. Whether selected for its symbolic meaning, its durability for everyday wear, or its rarity and value, one of these four gems is sure to resonate. As the month with the most birthstones, December truly provides a small treasure chest of options, allowing each individual to find a gem that not only marks their birth but also reflects their personal journey and style.