December is a month rich in tradition, symbolism, and celebration. Its gemstone lore reflects the same depth, with a unique distinction: it is one of the few months with multiple birthstones. The December birthstones—blue topaz, turquoise, zircon, and tanzanite—have been associated with the zodiac signs of Sagittarius and Capricorn, which span the month. These gemstones are not only admired for their beauty but also for the spiritual and historical significance they carry. From ancient talismans to modern jewelry, December birthstones offer a fascinating intersection of geology, astrology, and cultural heritage.
This article explores the zodiac associations of December’s birthstones, their gemological properties, their historical uses, and the beliefs that have shaped their meanings over time. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, this guide provides an in-depth look at the December birthstones and their connections to the zodiac.
History and Lore
The concept of birthstones dates back centuries, with early records tracing to the Breastplate of Aaron, described in the Book of Exodus. This sacred Jewish artifact, worn by the High Priest, featured twelve gemstones representing the twelve tribes of Israel. Over time, these stones became associated with the zodiac and eventually with the months of the year, evolving into what we now recognize as birthstones.
December, as the final month of the year, has a particularly rich and varied history when it comes to its birthstones. The earliest known December birthstone was ruby, derived from ancient biblical interpretations. However, modern birthstone lists have evolved significantly. In 1870, turquoise was designated as the December birthstone by Tiffany & Co. in their "Gregorian Birthstone Poems." By 1912, turquoise remained primary, but lapis lazuli was also recognized as an alternative by the National Association of Jewelers. In 1952, zircon was added to the list, and in 2002, the American Gem Trade Association introduced tanzanite as a December birthstone, expanding the options for those born in this month.
These changes reflect the dynamic nature of birthstone traditions, influenced by both cultural trends and the gemstone trade. December’s birthstones, particularly turquoise, have deep historical roots. Archaeological evidence suggests that turquoise was used as early as 7000 BCE in burial sites in western Iran. In ancient Egypt, it was considered a sacred stone linked to the goddess Hathor and was used in amulets and ceremonial objects to bring good fortune and protection.
Tanzanite, on the other hand, is a relatively modern discovery. Found in the foothills of Mount Kilimanjaro in Tanzania in 1967, it was officially recognized as a birthstone in 2002. According to Maasai legend, the stone was created when lightning struck the earth, turning the rocks a vibrant blue. This origin story adds a unique cultural dimension to its allure.
Zircon has also been a cherished gemstone for millennia. The Greeks believed it to be a fire-bearing stone, and its name may have come from the Greek word topazos, referring to an island in the Red Sea. Blue zircon, in particular, has been prized for its brilliance and clarity, making it a popular alternative to diamonds in jewelry.
Blue topaz, the fourth December birthstone, has a more varied etymology. Some believe its name comes from the Sanskrit word Tapas, meaning “fire,” while others link it to the Greek word Topazos. Regardless of its origin, blue topaz has been associated with calmness, communication, and emotional balance in various cultures.
The zodiac signs associated with December are Sagittarius (November 22–December 21) and Capricorn (December 22–January 19). Each of the December birthstones is believed to resonate with these signs, amplifying their natural traits. For example, turquoise and tanzanite are linked to Sagittarius, enhancing qualities like adventure and intuition, while blue topaz and zircon are associated with Capricorn, supporting ambition and wisdom.
Geological Formation and Sources
Each of December’s birthstones has a unique geological origin and set of properties that make it distinctive in the world of gemology.
Blue Topaz
Blue topaz is a silicate mineral composed primarily of aluminum, fluorine, and silicon (Al₂SiO₄(F,OH)₂). Its blue color is the result of irradiation, a process that can occur naturally in the earth or be induced in laboratories to enhance the stone’s color. Blue topaz is typically found in pegmatite deposits and is one of the hardest December birthstones, with a Mohs hardness of 8. This makes it ideal for everyday wear and durable in jewelry.
Blue topaz is most commonly mined in Brazil, the United States, Mexico, and Nigeria. Brazil, in particular, is known for producing large, high-quality blue topaz crystals.
Turquoise
Turquoise is a phosphate mineral composed of copper, aluminum, and phosphorus, with a chemical formula of CuAl₆(PO₄)₄(OH)₈·4H₂O. Its characteristic blue and green hues are due to the presence of copper. Turquoise forms in the oxidized zones of copper deposits and is often found in arid regions where it is exposed to surface water.
Historically, the most famous sources of turquoise include Persia (modern-day Iran), Egypt, and China. Today, major turquoise producers include the United States (particularly Nevada and New Mexico), Iran, China, and Egypt. Turquoise is a softer gemstone, with a Mohs hardness of 5–6, making it more delicate and requiring careful handling.
Zircon
Zircon is a zirconium silicate mineral with the chemical formula ZrSiO₄. It is known for its high refractive index and dispersion, giving it a diamond-like brilliance. Zircon occurs in a variety of colors, but blue zircon is the most popular for use as a birthstone.
Zircon is found in a range of geological settings, including metamorphic rocks and sand deposits. Significant sources include Australia, Burma (Myanmar), Sri Lanka, and the United States. Zircon has a Mohs hardness of 6–7.5, making it suitable for jewelry, though it requires care to avoid scratches and abrasions.
Tanzanite
Tanzanite is a rare and unique gemstone, composed of calcium aluminum silicate with the chemical formula CaAl₆(BO₃)₃(SiO₄)₃(OH)₄. Its deep blue and violet hues are the result of trace amounts of vanadium. Tanzanite is only found in a small area near Mount Kilimanjaro in Tanzania, making it one of the rarest gemstones in the world.
Tanzanite is relatively soft, with a Mohs hardness of 6–7, and it is sensitive to heat and light. It must be cut carefully to maximize its color and brilliance, and it requires special care to avoid fading or damage.
Gemological Properties
The gemological properties of December’s birthstones highlight their distinctiveness and versatility in jewelry. These properties include color, hardness, refractive index, and clarity.
| Gemstone | Color | Mohs Hardness | Refractive Index | Common Sources |
|---|---|---|---|---|
| Blue Topaz | Blue | 8 | 1.62–1.64 | Brazil, USA |
| Turquoise | Blue/Green | 5–6 | 1.61–1.65 | Nevada, Iran |
| Zircon | Blue | 6–7.5 | 1.92–2.00 | Sri Lanka, Burma |
| Tanzanite | Blue/Purple | 6–7 | 1.694–1.701 | Tanzania |
Blue Topaz is prized for its clarity and brilliance. It is often cut in a brilliant or princess style to enhance its sparkle. Its high hardness makes it suitable for all types of jewelry, including rings and bracelets.
Turquoise is known for its opaque texture and chatoyancy, a shimmering effect caused by the presence of fibrous minerals. It is often stabilized with resin to improve its durability. Due to its softness, turquoise is best suited for earrings and pendants rather than rings or bracelets.
Zircon, particularly blue zircon, is noted for its high refractive index and dispersion, which give it a fire-like sparkle. It is often cut in a brilliant or emerald style to showcase its clarity and brilliance. Zircon can be found in a range of colors, but blue is the most popular for use in jewelry.
Tanzanite is unique for its pleochroism, a property that allows it to display different colors depending on the angle of light. It is typically cut in a cushion or oval style to enhance its color and reduce light sensitivity. Tanzanite is also sensitive to heat, so it must be handled carefully during cutting and setting.
Symbolism and Metaphysical Beliefs
The December birthstones carry deep symbolic meanings and metaphysical properties that have been revered across cultures and time periods.
Blue Topaz
Blue topaz is associated with calmness, communication, and emotional balance. It is believed to enhance the throat chakra, promoting clear and confident self-expression. Many wear blue topaz to soothe anxiety, foster mental clarity, and encourage inner peace. It is also considered a stone of loyalty and love, making it a meaningful gift for those celebrating relationships or new beginnings.
Turquoise
Turquoise has long been regarded as a protective stone. In ancient Egypt, it was believed to ward off evil spirits and bring good fortune. It was also associated with the goddess Hathor and was used in amulets and ceremonial objects. Turquoise is thought to promote self-expression, compassion, and emotional healing. It is also believed to strengthen the immune system and aid in detoxification.
Zircon
Zircon is known for its ability to enhance mental clarity, intuition, and grounding. It is believed to help the wearer stay focused and make wise decisions. Zircon is also associated with spiritual transformation and is used in meditation to deepen awareness and connection to higher realms.
Tanzanite
Tanzanite is linked to transformation, spiritual growth, and creativity. It is believed to help individuals release old patterns and embrace new beginnings. Tanzanite is also associated with intuition and psychic abilities, making it a popular stone for those seeking to expand their spiritual awareness.
Care and Cleaning
Proper care is essential for maintaining the beauty and longevity of December birthstones, particularly for those with lower hardness and sensitivity to light or heat.
Blue Topaz
Blue topaz is relatively durable and can be cleaned with warm, soapy water and a soft cloth. Avoid using ultrasonic or steam cleaners, as they can cause damage. Store blue topaz separately to prevent scratches.
Turquoise
Turquoise is a softer gemstone and requires careful handling. Clean it with a damp cloth and mild soap, avoiding harsh chemicals. It should not be exposed to extreme heat or dry environments, as it can dehydrate and crack.
Zircon
Zircon is best cleaned with warm water and a soft brush. Avoid exposure to harsh chemicals, as they can damage the stone. Zircon should be stored in a soft pouch to prevent scratches.
Tanzanite
Tanzanite is sensitive to heat and light and should be cleaned with a soft cloth and mild detergent. Avoid using ultrasonic or steam cleaners, as they can cause fading or damage. Tanzanite should be stored in a cool, dark place to preserve its color.
Conclusion
December’s birthstones—blue topaz, turquoise, zircon, and tanzanite—offer a fascinating blend of history, symbolism, and gemological beauty. Each stone has its own unique properties, making them suitable for different types of jewelry and personal styles. Their associations with the zodiac signs of Sagittarius and Capricorn highlight their role in amplifying positive traits such as wisdom, ambition, and transformation.
From the ancient use of turquoise in Egyptian ceremonies to the modern discovery of tanzanite in Tanzania, these gemstones reflect the evolving nature of birthstone traditions. Whether worn for their beauty, their meaning, or their connection to the zodiac, December’s birthstones continue to captivate and inspire.
Understanding the properties, symbolism, and care requirements of these gemstones allows for a deeper appreciation of their value and significance. Whether you are selecting a birthstone for yourself or a loved one, these gems offer a meaningful and elegant choice for any occasion.