December, the final month of the year, is marked by a variety of gemstones that reflect the cool tones of winter and the warmth of festive celebrations. The birthstones of December include a diverse array of blue-hued gems—blue topaz, blue zircon, tanzanite, and turquoise. Each of these gemstones carries a unique set of properties, historical significance, and cultural symbolism, making them not only beautiful but also meaningful choices for those born in this month. This article delves into the characteristics, origins, and significance of each of these December birthstones, offering insight into their gemological attributes and the reasons behind their enduring appeal.
A Historical Overview of December Birthstones
The tradition of assigning gemstones to each month of the year dates back centuries, with roots in ancient Jewish, Egyptian, and medieval European cultures. Over time, these associations evolved, and the list of December birthstones expanded to include multiple gems. This expansion allows for greater flexibility in choosing a gemstone that aligns with an individual’s preferences, budget, and style.
Historically, December birthstones have been linked with protection, wisdom, and good fortune. Turquoise and lapis lazuli, for instance, have been used since ancient times by royalty and spiritual leaders. These stones were believed to bring clarity, strength, and spiritual insight. More recently, the list of December birthstones has been updated to include modern gems such as blue topaz and tanzanite, which are prized for their vibrant colors and durability.
Today, December is associated with five recognized birthstones: blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise. While turquoise and lapis lazuli are considered traditional December birthstones, blue zircon, blue topaz, and tanzanite are recognized as modern additions. This diversity reflects both the rich history and the evolving nature of gemstone appreciation.
Geological Formation and Sources
Each December birthstone is formed under distinct geological conditions, resulting in unique properties and appearances. Understanding the formation and sources of these gemstones provides insight into their rarity, durability, and aesthetic qualities.
Blue Topaz
Blue topaz is a variety of the mineral topaz, which is composed of silicate of aluminum and fluorine (Al₂SiO₄(F,OH)₂). Natural blue topaz is relatively rare, and most blue topaz on the market is enhanced through irradiation and heat treatment. This gemstone is typically found in Brazil, the United States, and Nigeria. It is known for its clarity and brilliance, making it a popular choice for jewelry.
Blue Zircon
Zircon is a zirconium silicate (ZrSiO₄) that occurs in various colors, including blue, yellow, and red. Blue zircon is created through heat treatment, which enhances its natural color. This gemstone is found in countries such as Cambodia, Thailand, and Australia. Blue zircon is notable for its high refractive index and strong dispersion, which give it a brilliant fire and rainbow-like flashes.
Tanzanite
Tanzanite is a trichroic gemstone that displays different colors depending on the viewing angle. It is a variety of the mineral zoisite (Ca₂Al₃(SiO₄)(OH)₃·(OH)·(H₂O)). Tanzanite is only found in one location in the world—near Mount Kilimanjaro in Tanzania. This exclusivity contributes to its value and desirability. Tanzanite is typically treated with heat to enhance its blue to violet hues.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper (Al₂(OH)₃PO₄·H₂O). It forms in arid regions where copper-rich rocks are exposed to weathering and groundwater. Turquoise is often found in association with minerals such as quartz, calcite, and pyrite. Major sources of turquoise include the United States (particularly Nevada and Arizona), Iran, and China. The presence of matrix (the surrounding rock) can affect the color and appearance of turquoise, making each piece unique.
Lapis Lazuli
Lapis lazuli is a metamorphic rock composed primarily of lazurite (a sodium calcium aluminum silicate), with additional minerals such as pyrite and calcite. It is known for its deep blue color and golden flecks of pyrite. Lapis lazuli is primarily mined in Afghanistan, with additional sources in Russia, Chile, and the United States. It has been used for thousands of years in art and jewelry, particularly in ancient Egypt and Mesopotamia.
Gemological Properties
Understanding the gemological properties of each December birthstone is essential for appreciating their beauty and durability. These properties include hardness, refractive index, color, and other physical characteristics that influence their use in jewelry.
Hardness and Durability
Blue Topaz: With a hardness of 8 on the Mohs scale, blue topaz is a durable gemstone that can withstand daily wear. It is relatively tough and resistant to scratches, making it suitable for rings and other types of jewelry.
Blue Zircon: Blue zircon has a hardness of 6 to 7.5, which makes it less durable than blue topaz. While it is still a good choice for jewelry, it requires careful handling to avoid scratches and chipping.
Tanzanite: Tanzanite has a hardness of 6 to 7, which is moderate for a gemstone. It is sensitive to heat and can fade if exposed to high temperatures. It is best suited for jewelry that is worn occasionally rather than daily.
Turquoise: Turquoise has a hardness of 5 to 6 and is relatively soft. It is also porous, making it susceptible to damage from moisture and chemicals. It is best suited for pendants and earrings rather than rings.
Lapis Lazuli: Lapis lazuli has a hardness of 5 to 6 and is a porous stone. It can be easily damaged by harsh chemicals and abrasion. Like turquoise, it is best suited for pendants and earrings.
Refractive Index and Dispersion
Blue Topaz: Blue topaz has a refractive index of 1.62 to 1.64 and is singly refractive. It has moderate dispersion, which gives it a subtle brilliance.
Blue Zircon: Blue zircon has a refractive index of 1.92 to 2.00 and is doubly refractive. It has strong dispersion, which creates a noticeable fire when light enters the stone.
Tanzanite: Tanzanite has a refractive index of 1.694 to 1.701 and is trichroic. It has moderate dispersion and is known for its deep blue to violet color.
Turquoise: Turquoise is an opaque gemstone and does not have a refractive index. Its color is due to the presence of copper, and it lacks the brilliance of transparent gemstones.
Lapis Lazuli: Lapis lazuli is also an opaque gemstone and does not have a refractive index. Its color comes from lazurite, and its golden flecks of pyrite add to its visual appeal.
Symbolism and Cultural Significance
December birthstones have long been associated with various symbolic meanings and cultural beliefs. These associations have evolved over time, influenced by historical practices, religious beliefs, and modern interpretations.
Blue Topaz
Blue topaz is often associated with calmness, serenity, and clarity. In ancient times, it was believed to bring good fortune and protection to the wearer. Today, blue topaz is seen as a symbol of strength and self-assurance. Its clear blue color is thought to promote mental clarity and emotional stability.
Blue Zircon
Blue zircon is known for its brilliant fire and rainbow-like flashes. It is often associated with wisdom, truth, and spiritual insight. In ancient times, zircon was believed to enhance the wearer’s ability to foresee the future. Its high refractive index and strong dispersion make it a symbol of brilliance and vitality.
Tanzanite
Tanzanite is a relatively new gemstone, having been discovered in the 1960s. It is associated with transformation, intuition, and spiritual awakening. Its unique blue to violet color is believed to promote emotional healing and inner peace. As a gemstone found only in Tanzania, it is also associated with uniqueness and exclusivity.
Turquoise
Turquoise has been used for thousands of years in jewelry and adornment. In ancient Egypt, it was believed to bring protection and good fortune. In Native American cultures, turquoise is considered a sacred stone that represents health, harmony, and spiritual connection. It is often used in ceremonial jewelry and is believed to enhance communication with the spirit world.
Lapis Lazuli
Lapis lazuli has been used in art and jewelry for over 7,000 years. In ancient Egypt, it was associated with the goddess Isis and was believed to bring wisdom and truth. In medieval Europe, it was used in religious art and was considered a stone of nobility. Today, lapis lazuli is associated with intellectual growth, spiritual insight, and inner peace.
Care and Maintenance
Proper care is essential for preserving the beauty and longevity of December birthstone jewelry. Each gemstone requires specific care due to its unique properties and vulnerabilities.
Blue Topaz
Blue topaz is relatively durable and can be cleaned with warm, soapy water and a soft brush. It is resistant to most household chemicals and can be worn daily with minimal risk of damage.
Blue Zircon
Blue zircon is less durable than blue topaz and should be handled with care. It should be cleaned gently with a soft cloth and warm water. It is sensitive to harsh chemicals and should not be exposed to high heat.
Tanzanite
Tanzanite is sensitive to heat and can fade if exposed to high temperatures. It should be stored away from direct sunlight and should not be cleaned with ultrasonic cleaners or steam. A gentle wipe with a soft cloth and warm water is sufficient for cleaning.
Turquoise
Turquoise is a soft and porous gemstone that requires careful handling. It should be kept away from moisture and chemicals and should not be cleaned with ultrasonic cleaners. A gentle wipe with a dry cloth is the best way to clean turquoise.
Lapis Lazuli
Lapis lazuli is also a soft and porous gemstone. It should be kept away from harsh chemicals and abrasive materials. A gentle wipe with a dry cloth is the best way to clean lapis lazuli, and it should be stored in a cool, dry place.
Conclusion
The birthstones of December—blue topaz, blue zircon, tanzanite, and turquoise—offer a rich and diverse selection of gemstones that reflect the cool tones of winter and the warmth of human history. Each of these gemstones has unique properties, origins, and symbolic meanings, making them meaningful choices for those born in December. Whether chosen for their beauty, durability, or cultural significance, these gemstones continue to captivate and inspire, connecting wearers to the past and the present in a meaningful way.