December, the final month of the year, is celebrated not only for its festive traditions and seasonal moods but also for the diversity of gemstones it embraces as its birthstones. Unlike months with a single representative stone, December is graced with multiple birthstones—each offering a unique blend of color, history, and symbolism. These gemstones include blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise. Together, they reflect the chill and charm of winter, the richness of ancient traditions, and the modern appreciation for vibrant gemstone choices.
This article delves into the fascinating world of December's birthstones, exploring their geological formation, cultural significance, and the reasons behind their selection as the month's symbolic gems. Whether you are a gemstone enthusiast, a jewelry buyer, or simply curious about the meaning behind your birthstone, this guide offers a comprehensive look at the stones that make December unique.
History and Lore
The concept of birthstones is deeply rooted in ancient traditions, with early references found in biblical texts, medieval manuscripts, and even in the jewelry of ancient civilizations. The earliest known birthstone list comes from the Book of Exodus in the Bible, which lists twelve gemstones associated with the twelve tribes of Israel. However, the association of these stones with months of the year came much later, evolving over centuries of cultural and religious influence.
For December, the earliest recorded birthstone was ruby, as referenced in the biblical lists. However, by the 19th century, the gemstone list had undergone significant changes. In 1870, turquoise was designated as the primary birthstone for December in a pamphlet titled “Gregorian Birthstone Poems” by Tiffany & Co. This was followed in 1912 by the National Association of Jewellers (now Jewellers of America), who listed turquoise as the primary December birthstone and lapis lazuli as an alternative.
In 1952, the Jewelry Industry Council of America added zircon to the list, particularly blue zircon, which was valued for its brilliance and range of colors. Then, in 2002, tanzanite was officially recognized as a December birthstone in the United States, adding a new dimension to the collection with its unique violet-blue hue.
Today, the December birthstone list includes five gemstones: blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise. This diverse selection reflects the month’s cultural and historical evolution, as well as the modern appreciation for variety in both color and meaning.
The inclusion of multiple birthstones for December serves a practical purpose: it provides a range of options that cater to different tastes, budgets, and symbolic preferences. Whether someone prefers the cool, serene blue of topaz or the vibrant violet of tanzanite, there is a December birthstone to suit every personality and occasion.
Geological Formation and Sources
Each of December’s birthstones has its own geological story, shaped by the Earth’s natural processes over millions of years. Understanding the formation and sources of these gemstones adds depth to their allure and significance.
Blue Zircon
Zircon is a mineral that forms in igneous rocks, particularly in granite and basalt, as well as in metamorphic and sedimentary rocks. The blue color of zircon is achieved through a heat treatment process that alters the crystal structure of the gemstone. This transformation is a relatively modern technique and has contributed to the popularity of blue zircon as a December birthstone.
Zircon is found in various parts of the world, including Brazil, Australia, India, and Madagascar. However, blue zircon is most commonly sourced from Australia and Brazil, where large deposits of zirconium-rich minerals are processed to produce the vibrant blue hue.
Blue Topaz
Topaz is a silicate mineral that forms in pegmatite rocks—coarse-grained igneous rocks rich in quartz and feldspar. Blue topaz, the most well-known variety, is naturally colorless but is often irradiated and heat-treated to produce its signature blue color. This treatment is stable and permanent, making blue topaz a popular choice for jewelry.
The primary sources of topaz include Brazil, Mexico, and Russia. However, blue topaz is mostly produced in Brazil, where large deposits of colorless topaz are treated to create the blue variety associated with December.
Tanzanite
Tanzanite is a relatively rare gemstone, first discovered in Tanzania in 1967. It is a variety of the mineral columbite, which is a niobium-rich silicate. Tanzanite forms in metamorphic rocks, particularly in the area surrounding Mount Kilimanjaro, where the unique geological conditions create the perfect environment for its development.
The violet-blue color of tanzanite is due to the presence of vanadium and the way light interacts with the crystal structure. Tanzanite is only found in Tanzania, making it one of the most geographically exclusive gemstones in the world.
Lapis Lazuli
Lapis lazuli is a metamorphic rock composed primarily of lazurite, a sodium calcium aluminum silicate. It also contains other minerals like calcite and pyrite, which contribute to its deep blue color and golden flecks. Lapis lazuli forms under high pressure and temperature conditions, typically in the Caucasus Mountains, Egypt, and Afghanistan.
Afghanistan is the most significant source of lapis lazuli, with the Badakhshan region producing the highest quality stones for centuries. Lapis lazuli was highly prized in ancient Egypt and Mesopotamia for its rich blue color, which was associated with the heavens and divine knowledge.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, formed in the oxidation zones of copper deposits. It is typically found in arid regions where water has slowly seeped through the rock, depositing the necessary minerals to form turquoise.
The most famous sources of turquoise include Nevada and Arizona in the United States, Iran, and Mongolia. American turquoise, particularly from the Cerrillos Mines in New Mexico and the Sleeping Beauty Mine in Arizona, is highly valued for its rich blue color and minimal matrix (the surrounding rock).
Turquoise has been mined and used for thousands of years, with ancient cultures such as the Egyptians, Aztecs, and Native Americans using it in jewelry, ceremonial objects, and even in mummification practices.
Gemological Properties
Understanding the physical and optical properties of December’s birthstones provides insight into their beauty and durability. Each gemstone has distinct characteristics that influence its use in jewelry and its care requirements.
Blue Zircon
- Chemical Formula: ZrSiO₄
- Crystal System: Tetragonal
- Hardness (Mohs Scale): 6.5–7.5
- Color: Blue (achieved through heat treatment)
- Refractive Index: 1.92–2.01
- Luster: Vitreous
- Specific Gravity: 4.6–4.7
Blue zircon is known for its high refractive index and dispersion, giving it a brilliant, fiery appearance. It is relatively hard and durable, making it suitable for everyday wear in jewelry.
Blue Topaz
- Chemical Formula: Al₂SiO₄(F,OH)₂
- Crystal System: Orthorhombic
- Hardness (Mohs Scale): 8
- Color: Blue (colorless in nature, treated to blue)
- Refractive Index: 1.61–1.63
- Luster: Vitreous
- Specific Gravity: 3.53
Blue topaz is one of the hardest December birthstones, with a Mohs hardness of 8. This makes it highly durable and ideal for use in rings, bracelets, and other types of jewelry.
Tanzanite
- Chemical Formula: Ca₂Al₃(AlSiO₄)₃(OH)₄
- Crystal System: Trigonal
- Hardness (Mohs Scale): 6–7
- Color: Violet-blue to purple-blue
- Refractive Index: 1.694–1.701
- Luster: Vitreous to greasy
- Specific Gravity: 3.18–3.38
Tanzanite is known for its pleochroism, meaning it can display different colors depending on the angle of light. This gives it a unique and dynamic appearance. While it is relatively hard, it is also sensitive to heat and pressure, so it requires careful handling.
Lapis Lazuli
- Chemical Formula: (Na,Ca)₈(AlSiO₄)₆(S,SO₄,Cl)₁₋₂
- Crystal System: Isometric
- Hardness (Mohs Scale): 5–6
- Color: Deep blue with white and gold flecks
- Refractive Index: 1.50–1.70
- Luster: Vitreous to greasy
- Specific Gravity: 2.4–2.9
Lapis lazuli is a metamorphic rock rather than a single mineral, so its properties vary depending on the presence of other minerals like calcite and pyrite. It is relatively soft and can be easily scratched, making it better suited for pendants and earrings than for rings.
Turquoise
- Chemical Formula: CuAl₆(PO₄)₄(OH)₈·4H₂O
- Crystal System: Trigonal
- Hardness (Mohs Scale): 5–6
- Color: Blue to green, often with a matrix
- Refractive Index: 1.61–1.65
- Luster: Waxy to vitreous
- Specific Gravity: 2.6–2.8
Turquoise is a relatively soft gemstone, which makes it prone to scratches and damage. It is often stabilized with resins or oils to enhance its durability. The presence of a matrix (the surrounding rock) can vary from subtle to prominent, affecting the gemstone’s appearance and value.
| Gemstone | Hardness | Color | Origin | Treatments | Durability |
|---|---|---|---|---|---|
| Blue Zircon | 6.5–7.5 | Blue | Brazil, Australia | Heat treatment | High |
| Blue Topaz | 8 | Blue | Brazil, Mexico | Irradiation, heat | High |
| Tanzanite | 6–7 | Violet-blue | Tanzania | Heat treatment | Medium |
| Lapis Lazuli | 5–6 | Deep blue | Afghanistan | None | Low |
| Turquoise | 5–6 | Blue-green | US, Iran | Stabilization | Low |
Symbolism and Metaphysical Beliefs
Each of December’s birthstones carries its own set of symbolic meanings and metaphysical properties, many of which have been passed down through generations of cultural and spiritual traditions.
Blue Zircon
Zircon has long been associated with joy, emotional balance, and spiritual insight. It is believed to enhance intuition and bring a sense of calm to the wearer. Zircon is also said to promote healing and protection, particularly from negative energies and psychic attacks.
In ancient times, zircon was thought to be a stone of time, given its presence in some of the oldest rocks on Earth. It was also used in protective amulets and was believed to bring good fortune and prosperity.
Blue Topaz
Topaz is known as a stone of self-esteem and emotional balance. It is believed to help the wearer gain confidence and clarity in their thoughts, making it a popular stone for students and those in need of mental focus.
Topaz is also associated with calmness and inner peace. It is used in meditation to help the mind stay centered and to promote a sense of serenity. In some cultures, topaz is believed to protect the wearer from nightmares and negative dreams.
Tanzanite
Tanzanite is considered a stone of transformation and spiritual growth. It is believed to help the wearer connect with their higher self and to encourage emotional healing and self-acceptance.
Tanzanite is also associated with love and compassion, making it a popular choice for engagement rings and wedding bands. It is believed to enhance communication and emotional understanding between partners.
Lapis Lazuli
Lapis lazuli is one of the oldest known gemstones and has been revered for its wisdom, truth, and intellectual power. It is believed to enhance mental clarity and stimulate the pursuit of knowledge.
Lapis lazuli is also associated with royalty and nobility, as it was often used in jewelry and ceremonial objects by ancient rulers. It is believed to promote inner peace and spiritual awakening, making it a popular stone in meditation practices.
Turquoise
Turquoise is one of the most spiritually significant gemstones in human history. It is believed to offer protection, good fortune, and a connection to the divine. In many cultures, it was used in ceremonial objects, amulets, and even in the burial of the dead.
Turquoise is also associated with healing and emotional balance. It is believed to calm the mind and promote a sense of well-being. In some traditions, it is used to absorb negative energy and to promote positive emotions.
Care and Cleaning
Proper care is essential to maintaining the beauty and longevity of any gemstone. The following guidelines provide specific care instructions for each of December’s birthstones, based on their physical properties and sensitivity to external factors.
Blue Zircon
Zircon is relatively durable, but it is sensitive to high heat and sudden temperature changes. Avoid exposing it to direct sunlight for extended periods, as this can cause fading. Clean zircon with a soft cloth and mild soap, and avoid using ultrasonic or steam cleaners, which can damage the stone.
Blue Topaz
Topaz is one of the hardest December birthstones and is highly resistant to scratches. It can be cleaned with warm, soapy water and a soft brush. Avoid using ultrasonic cleaners, as they can damage the internal structure of the gemstone. Store topaz separately from other gemstones to prevent scratching.
Tanzanite
Tanzanite is sensitive to heat and pressure and should be handled with care. Avoid exposing it to direct sunlight or high temperatures, as this can cause it to fade or crack. Clean tanzanite with a soft cloth and mild soap, and avoid using ultrasonic or steam cleaners.
Lapis Lazuli
Lapis lazuli is a relatively soft gemstone and is prone to scratches and damage. It should be stored separately from harder gemstones and cleaned with a soft cloth and mild soap. Avoid using ultrasonic or steam cleaners, as they can cause the stone to crack or become dull.
Turquoise
Turquoise is a soft and porous gemstone that is easily damaged by heat, chemicals, and moisture. It should be stored in a dry place and cleaned with a soft cloth and mild soap. Avoid using ultrasonic or steam cleaners, and never expose turquoise to harsh chemicals or direct sunlight.
Conclusion
December’s birthstones—blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise—offer a rich tapestry of history, symbolism, and beauty. Each gemstone has its own unique geological story, cultural significance, and metaphysical properties, making them more than just decorative objects but meaningful symbols of identity and tradition.
Whether you are drawn to the brilliance of blue zircon, the serenity of blue topaz, the rarity of tanzanite, the wisdom of lapis lazuli, or the spiritual protection of turquoise, there is a December birthstone that resonates with your personal journey. These stones are not only beautiful but also deeply connected to the human experience, reflecting the changing seasons, the passage of time, and the enduring power of gemstones in our lives.
By understanding the history, properties, and care requirements of these gemstones, you can appreciate their value not only as jewelry but as artifacts of culture, nature, and human history.