December is unique in the realm of birthstones, offering not one, but multiple gemstones that capture the essence of the winter season. Among the choices available to those born in this month, blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise stand out for their vibrant colors, rich historical significance, and diverse cultural meanings. These gemstones have been cherished across civilizations, from ancient royalty to modern jewelry design, and each brings its own distinct charm and properties to the table.
This article delves into the world of December’s birthstones, exploring their geological origins, gemological properties, and the symbolism that has been attributed to them over the centuries. Whether you're a gemstone enthusiast, a jewelry buyer, or simply curious about the meaning behind these stones, this in-depth look will provide a comprehensive understanding of what makes December’s birthstones so special.
History and Lore of December Birthstones
The tradition of associating gemstones with specific months of the year has deep historical roots. Ancient cultures, including those of the Babylonians and Egyptians, used gemstones as protective talismans and symbols of divine favor. By the medieval period, the practice of assigning gemstones to months had become widespread, and today, these associations continue to hold cultural and personal significance for many.
In the case of December, the selection of multiple birthstones reflects the diversity of blue hues that have been valued throughout history. The inclusion of lapis lazuli and turquoise as traditional December birthstones dates back to ancient times. Lapis lazuli, with its deep blue tones and flecks of gold pyrite, was highly prized by Egyptian royalty and was often used in ceremonial artifacts. The ancient Egyptians believed it brought wisdom and truth, and it was even ground into powder to make makeup for the pharaohs.
Turquoise, another traditional December birthstone, has a long and storied history in Mesoamerican and East Asian cultures. It was considered a sacred stone by the Aztecs and was often used in religious rituals. In Chinese and Persian cultures, turquoise was believed to offer protection and bring good fortune. Its use in jewelry and ornamentation has persisted through the centuries, and today it remains a popular choice for those seeking a connection to tradition.
Modern December birthstones such as blue topaz, zircon, and tanzanite were added to the list in more recent times, reflecting evolving tastes and the discovery of new gem materials. Blue topaz, for instance, became a popular choice in the 20th century due to its affordability and brilliant blue color. Zircon, with its high refractive index and fire, has also gained popularity as a December birthstone. Tanzanite, discovered in the 1960s in Tanzania, is perhaps the most recent addition to the list, and its striking blue-violet hues have made it a sought-after gem.
The selection of multiple birthstones for December allows for a variety of options in color, price, and personal meaning. This diversity caters to different tastes and histories, ensuring that individuals born in December have a gemstone that resonates with their personal journey and aesthetic preferences.
Geological Formation and Sources of December Birthstones
Each of December’s birthstones has a unique geological origin and set of properties that contribute to its allure. Understanding how these gemstones are formed and where they are found can provide insight into their rarity and beauty.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It forms in the oxidation zones of copper deposits, where water percolates through the rock and carries dissolved copper and other minerals. Over time, these minerals precipitate and form turquoise in cavities and fractures within the rock. Turquoise is typically found in arid environments, particularly in weathered volcanic and sedimentary rock.
The most well-known sources of turquoise are in the United States, particularly in New Mexico, Arizona, and Nevada. Other notable sources include Iran, Egypt, China, and Mexico. The quality and color of turquoise can vary depending on the specific location and the presence of impurities such as iron and other minerals, which can affect the stone's hue.
Lapis Lazuli
Lapis lazuli is a metamorphic rock composed primarily of lazurite, a feldspathoid mineral, along with other minerals such as pyrite, calcite, and diopside. It forms under high-pressure conditions in the presence of sodium-rich materials. The deep blue color of lapis lazuli comes from the presence of lazurite, while the golden flecks of pyrite add to its visual appeal.
The most famous source of lapis lazuli is the Kafiristan region of Afghanistan, where it has been mined for thousands of years. Other sources include Russia, Chile, Canada, and the United States. Lapis lazuli from Afghanistan is considered the finest due to its rich blue color and high-quality composition.
Blue Zircon
Zircon is a silicate mineral with the chemical formula ZrSiO₄. It is one of the oldest minerals on Earth, with some zircon crystals dating back over 4 billion years. Zircon forms in a variety of geological settings, including igneous rocks, metamorphic rocks, and sedimentary deposits. The blue color of zircon is typically achieved through heat treatment, which alters the crystal structure and enhances the color.
Zircon is found in many parts of the world, including Australia, Brazil, Cambodia, India, and the United States. The most highly valued zircon for jewelry is often sourced from these regions, where it is cut and polished to bring out its brilliance and fire.
Blue Topaz
Topaz is a silicate mineral with the chemical formula Al₂SiO₄(F,OH)₂. It forms in igneous rocks such as granite and rhyolite, as well as in metamorphic and sedimentary environments. Blue topaz is not found in nature in its blue form; instead, it is typically treated with irradiation and heat to achieve its beautiful blue color.
Brazil is the primary source of blue topaz, with large deposits found in the state of Minas Gerais. Other sources include Nigeria, the United States, and Mexico. The treatment process that creates blue topaz has allowed for the production of high-quality, affordable gemstones that are popular in jewelry.
Tanzanite
Tanzanite is a variety of the mineral zoisite, with the chemical formula Ca₂Al₃(SiO₄)(OH)₃·(OH). It was discovered in 1967 near Mount Kilimanjaro in Tanzania, and it is one of the few gemstones that are exclusively found in a single location. Tanzanite forms in metamorphic rocks, specifically in schist and gneiss, where it is transformed under high heat and pressure.
The blue-violet color of tanzanite is due to trace amounts of vanadium in the crystal structure. The gem is known for its strong pleochroism, meaning it can display different colors depending on the angle of view. Tanzanite is a relatively recent addition to the list of December birthstones, but its unique color and limited availability have made it a popular choice for modern jewelry.
Gemological Properties of December Birthstones
Each of December’s birthstones has distinct gemological properties that contribute to its beauty and durability. These properties include hardness, refractive index, color, and clarity, which are important factors in gemstone selection and care.
Hardness and Durability
The Mohs scale of mineral hardness is a useful tool for understanding the durability of gemstones. On this scale, where 1 is the softest (talc) and 10 is the hardest (diamond), the hardness of December’s birthstones varies:
- Turquoise: 5–6
- Lapis Lazuli: 5–6
- Blue Zircon: 6–7.5
- Blue Topaz: 8
- Tanzanite: 6–7
Turquoise and lapis lazuli are relatively soft gemstones and require careful handling to avoid scratches and chips. Blue zircon and blue topaz are harder and more durable, making them suitable for everyday wear. Tanzanite, while relatively soft, is still a popular choice for jewelry due to its vibrant color and affordability.
Refractive Index and Luster
The refractive index of a gemstone determines how light interacts with it, affecting its brilliance and sparkle. The refractive index and luster of December’s birthstones are as follows:
- Turquoise: 1.61–1.63 (waxy luster)
- Lapis Lazuli: 1.50–1.70 (waxy to greasy luster)
- Blue Zircon: 1.92–2.00 (glassy luster)
- Blue Topaz: 1.62–1.63 (glassy luster)
- Tanzanite: 1.69–1.70 (glassy luster)
Zircon and tanzanite have the highest refractive indices among December’s birthstones, which contributes to their brilliance and fire. Turquoise and lapis lazuli, being opaque, have a waxy or greasy luster and are less reflective than the other stones.
Color and Clarity
The color of a gemstone is one of its most important characteristics, as it contributes to its aesthetic appeal and value. December’s birthstones are known for their beautiful blue hues, though they can vary in shade and intensity:
- Turquoise: Robin’s egg blue to greenish-blue
- Lapis Lazuli: Deep blue with flecks of gold pyrite
- Blue Zircon: Blue to violet-blue
- Blue Topaz: Calm, serene blue
- Tanzanite: Blue-violet to violet-blue
Clarity is less of a concern for turquoise and lapis lazuli, as they are opaque and do not require internal clarity. Zircon, topaz, and tanzanite, however, benefit from good clarity and are often cut to enhance their brilliance.
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been associated with various symbolic meanings and metaphysical properties. These beliefs have influenced the use of gemstones in jewelry, rituals, and personal adornment.
Turquoise
Turquoise has long been considered a stone of protection and good fortune. In many cultures, it is believed to dispel negative energy and promote positive emotions. It is also associated with wisdom, intuition, and spiritual growth. In Native American traditions, turquoise is considered a sacred stone that connects the earth and sky. It is often used in rituals and ceremonies to invoke harmony and balance.
Lapis Lazuli
Lapis lazuli is associated with wisdom, truth, and enlightenment. It has been used by ancient civilizations to enhance intellectual abilities and stimulate a quest for knowledge. The golden flecks of pyrite in lapis lazuli are believed to represent the sun and are associated with the power of the mind. It is also considered a stone of royalty and is believed to bring a sense of calm and serenity.
Blue Zircon
Zircon is known for its brilliance and fire, and it is believed to bring clarity and insight to the wearer. It is associated with the heart and is believed to enhance love and emotional well-being. Zircon is also considered a stone of transformation, helping individuals to release negative patterns and embrace new beginnings.
Blue Topaz
Blue topaz is associated with calmness, serenity, and emotional balance. It is believed to promote inner peace and help individuals to release inhibitions and prohibitions. It is also considered a stone of creativity and is believed to inspire artistic expression and imagination.
Tanzanite
Tanzanite is a relatively new gemstone in the world of metaphysical beliefs, but it has quickly gained popularity for its unique properties. It is associated with intuition, spiritual growth, and emotional healing. Tanzanite is believed to enhance the wearer's ability to communicate and express their emotions, making it a popular choice for those seeking emotional balance and clarity.
Care and Cleaning of December Birthstones
Proper care and cleaning are essential to maintaining the beauty and longevity of December’s birthstones. Due to their varying hardness and sensitivity to certain substances, it is important to handle these gemstones with care.
General Care Tips
- Avoid exposure to harsh chemicals: Turquoise, lapis lazuli, and tanzanite are particularly sensitive to acids, oils, and solvents. These substances can cause discoloration or damage to the stone.
- Store separately: To prevent scratches and abrasions, store each gemstone separately in a soft cloth or padded container.
- Avoid heat and sunlight: Prolonged exposure to heat or direct sunlight can cause some gemstones, particularly turquoise, to lose their color or become brittle.
Cleaning Methods
- Turquoise and Lapis Lazuli: These gemstones can be cleaned with a soft, damp cloth. Avoid using ultrasonic or steam cleaners, as they can cause damage.
- Blue Zircon, Blue Topaz, and Tanzanite: These harder gemstones can be cleaned with a mild detergent and a soft brush. They are also suitable for ultrasonic and steam cleaning, provided they are free of inclusions or fractures.
By following these simple care instructions, you can ensure that your December birthstones remain beautiful and vibrant for years to come.
Conclusion
December’s birthstones offer a rich and diverse selection of blue gemstones, each with its own unique properties, history, and symbolism. From the ancient traditions of lapis lazuli and turquoise to the modern elegance of blue topaz, zircon, and tanzanite, these stones reflect the beauty and complexity of the winter season.
Whether you are drawn to the deep blue of lapis lazuli, the vibrant hues of turquoise, or the brilliant fire of zircon and tanzanite, December’s birthstones provide a meaningful and beautiful way to connect with the past and express individuality. As you explore these gemstones, you will discover not only their physical beauty but also the stories and traditions that have made them cherished symbols of December.