December is a unique month in the world of gemstones, distinguished by its four official birthstones: blue topaz, turquoise, tanzanite, and zircon. Each of these gemstones offers distinct properties, histories, and symbolic meanings, making December a particularly fascinating month for gemstone enthusiasts and jewelry lovers. While many months are represented by a single gemstone, December’s selection reflects a blend of tradition, modernity, and affordability, ensuring that there is a gemstone to suit every taste and purpose.
This article explores each of the four December birthstones in detail, examining their geological properties, historical significance, cultural symbolism, and practical care. It also addresses the question of why December has multiple birthstones and how these gems have evolved in both meaning and popularity over time.
History and Lore
The practice of associating gemstones with specific months of the year has ancient roots, with early references found in Roman and medieval European traditions. However, the modern concept of birthstones—where each month is linked to a particular gem—was formalized in the 1912 publication by the American National Association of Jewelers (now known as the Jewelers of America). This list has been updated over time to include additional stones, particularly to offer more affordable and accessible options.
For December, the original list included turquoise and zircon, both of which have long-standing historical significance. Blue topaz and tanzanite were later added to the list, offering contemporary alternatives that have become increasingly popular in modern jewelry design.
Turquoise, one of the oldest known gemstones, has been used for thousands of years by ancient civilizations such as the Egyptians, Chinese, and Native Americans. It was highly valued not only for its beauty but also for its symbolic and protective properties. In ancient Egypt, turquoise was associated with the goddess Hathor and was often used in amulets to provide protection and good fortune. Native American cultures, particularly the Navajo and Hopi, have long used turquoise in jewelry and ceremonial objects, believing it to promote healing and spiritual balance.
Zircon, while less commonly known than turquoise, has also been treasured for its brilliance and fire. It has been used in ancient jewelry and was even mistaken for diamonds in some historical contexts due to its high refractive index. The stone has been found in archaeological sites dating back to the Bronze Age, indicating its long-standing appeal.
Tanzanite is a relatively new gemstone in the context of birthstone traditions. It was first discovered in Tanzania in 1967 and was named after the country where it is exclusively found. Its deep blue to violet hues quickly made it a favorite in modern jewelry, and it was officially added to the list of December birthstones to reflect its growing popularity.
Blue topaz, on the other hand, is a more recent addition in terms of its popularity as a birthstone. While topaz in general has been known for centuries, the blue variant was not widely available until the development of heat treatment techniques in the 20th century. This treatment, which transforms golden topaz into a striking blue, has made blue topaz a popular and affordable choice for December birthstone jewelry.
The inclusion of multiple birthstones for December reflects both historical tradition and modern consumer preferences. The diversity of options allows individuals to choose a gemstone that resonates with their personal style or symbolic meaning, whether they are drawn to the ancient allure of turquoise, the vibrant colors of tanzanite, the brilliance of zircon, or the clarity and durability of blue topaz.
Geological Formation and Sources
Understanding the geological origins of December’s birthstones provides insight into their rarity, beauty, and the conditions under which they form.
Blue Topaz
Blue topaz is a form of topaz, a silicate mineral with the chemical formula Al₂SiO₆. In its natural state, topaz is typically colorless or pale yellow, but the blue color in blue topaz is the result of radiation-induced color centers, a process that occurs naturally in some deposits or can be enhanced through controlled heat treatment. Blue topaz is known for its high hardness, ranking 8 on the Mohs scale, which makes it resistant to scratches and ideal for everyday jewelry.
Topaz is found in a variety of geological settings, including granite pegmatites, metamorphic rocks, and sand deposits. The most significant sources of blue topaz include Brazil, Mexico, and Nepal, where topaz is often mined from alluvial deposits. Brazil, in particular, is known for producing large, high-quality blue topaz specimens.
Turquoise
Turquoise is a phosphate mineral composed of copper, aluminum, and phosphorus, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It forms in weathered copper ore deposits, typically in arid climates where water percolates through the ground and interacts with copper sulfides. This process creates a porous, opaque stone with a characteristic blue to green color, depending on the presence of copper and iron.
Turquoise is found in various parts of the world, including Iran, the United States, China, and Russia. Iran has been a major source of turquoise for centuries and is known for producing the highly prized Persian blue variety. In the United States, Arizona and Nevada are the primary sources of turquoise, with the stone often mined from volcanic rock and sedimentary rock in arid regions.
Tanzanite
Tanzanite is a trigonal mineral composed of calcium aluminum silicate, with the chemical formula CaAl₆(SiO₄)₃(OH)₁₂. It is a relatively rare gemstone that was first discovered in 1967 in the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. The unique geological conditions of the area, including the presence of metamorphic rocks and hydrothermal activity, contributed to the formation of tanzanite.
Tanzanite is known for its trichroism, meaning it exhibits three different colors depending on the angle of light—blue, violet, and brown. The most desirable color is a deep blue to violet, achieved through controlled heating. Tanzanite has a Mohs hardness of 6 to 7, making it relatively durable but requiring careful handling to avoid scratches and chips.
Zircon
Zircon is a zirconium silicate mineral with the chemical formula ZrSiO₄. It is one of the oldest minerals found on Earth, with some zircon crystals dating back over 4 billion years. Zircon forms in a variety of geological environments, including igneous rocks, metamorphic rocks, and sedimentary deposits.
Zircon is found in numerous countries around the world, including Australia, Brazil, India, and Myanmar. The blue variety of zircon, known as blue zircon, is particularly popular as a December birthstone. It is created through heat treatment, which enhances the stone’s natural fire and color. Zircon has a Mohs hardness of 6 to 7.5, making it suitable for jewelry but requiring care to prevent damage.
Gemological Properties
Each of December’s birthstones has distinct gemological properties that influence their appearance, durability, and suitability for different types of jewelry.
Blue Topaz
- Color: Blue topaz ranges in color from sky blue to deep London blue, depending on the intensity of the color centers.
- Hardness: 8 on the Mohs scale, making it highly resistant to scratches and ideal for everyday wear.
- Clarity: Typically eye-clean, with minimal inclusions.
- Luster: Vitreous (glassy) luster.
- Refractive Index: 1.61 to 1.63.
- Cut: Commonly cut into brilliant, oval, and cushion shapes.
- Treatment: Naturally blue topaz is rare, and most blue topaz is heat-treated or irradiated to enhance color.
Turquoise
- Color: Ranges from light blue to deep green, depending on the presence of copper and iron.
- Hardness: 5 to 6 on the Mohs scale, making it relatively soft and prone to scratches and chips.
- Clarity: Opaque, with visible matrix patterns.
- Luster: Waxy to dull luster.
- Refractive Index: 1.61 to 1.65.
- Cut: Often cut into cabochons to showcase its color and matrix.
- Treatment: Frequently oiled or stabilized to enhance color and durability.
Tanzanite
- Color: Trichroic—blue, violet, and brown, with the most desirable being a deep blue to violet.
- Hardness: 6 to 7 on the Mohs scale, making it relatively durable but still requiring care.
- Clarity: Often eye-clean, though some inclusions may be present.
- Luster: Vitreous (glassy) luster.
- Refractive Index: 1.69 to 1.70.
- Cut: Commonly cut into brilliant and oval shapes.
- Treatment: Typically heat-treated to enhance color.
Zircon
- Color: Available in many colors, but the blue variety is most popular as a December birthstone.
- Hardness: 6 to 7.5 on the Mohs scale, making it relatively durable.
- Clarity: Often eye-clean, with minimal inclusions.
- Luster: Vitreous (glassy) luster.
- Refractive Index: 1.92 to 2.00, giving it a high refractive index and brilliant sparkle.
- Cut: Commonly cut into brilliant, oval, and emerald shapes.
- Treatment: Typically heat-treated to enhance color.
| Gemstone | Color Range | Hardness (Mohs) | Luster | Refractive Index | Common Cuts | Treatment |
|---|---|---|---|---|---|---|
| Blue Topaz | Sky blue to London blue | 8 | Vitreous | 1.61–1.63 | Brilliant, oval | Heat treatment |
| Turquoise | Blue to green | 5–6 | Waxy to dull | 1.61–1.65 | Cabochon | Stabilized/oiled |
| Tanzanite | Blue to violet | 6–7 | Vitreous | 1.69–1.70 | Oval, brilliant | Heat treatment |
| Zircon | Blue, yellow, red, etc. | 6–7.5 | Vitreous | 1.92–2.00 | Brilliant, oval | Heat treatment |
This table provides a clear comparison of the key gemological properties of December’s birthstones, highlighting their similarities and differences in terms of color, hardness, luster, and treatment.
Symbolism and Metaphysical Beliefs
Each of December’s birthstones carries its own symbolic and metaphysical significance, reflecting the cultural and historical contexts in which they have been used.
Blue Topaz
Blue topaz is associated with clarity, communication, and emotional balance. It is believed to promote clear thinking, calmness, and inner strength, making it a popular choice for those seeking to improve their communication skills or reduce stress. In metaphysical traditions, blue topaz is also said to enhance intuition and spiritual awareness.
Turquoise
Turquoise has long been regarded as a stone of protection, healing, and good fortune. It is believed to promote physical and emotional healing, as well as spiritual protection. In many cultures, turquoise has been used as a protective talisman, especially for warriors and travelers. It is also associated with soothing energy, helping to reduce anxiety and promote a sense of calm.
Tanzanite
Tanzanite is known for its transformative and spiritual properties. It is believed to support emotional healing, personal growth, and spiritual awakening. Tanzanite is associated with inner transformation, emotional balance, and heightened awareness. It is often used in meditation and energy work to help individuals connect with their higher self and gain deeper insight into their life path.
Zircon
Zircon is a stone of wisdom, prosperity, and clarity. It is believed to enhance intellectual capacity, memory, and decision-making skills. Zircon is also associated with prosperity and success, making it a popular choice for those seeking to improve their career or business ventures. In metaphysical traditions, zircon is also believed to protect against negative energies and promote mental clarity.
Care and Cleaning
Proper care is essential for maintaining the beauty and longevity of December’s birthstones. Each gemstone has specific care requirements based on its physical properties.
Blue Topaz
- Durability: Blue topaz is very durable, with a hardness of 8 on the Mohs scale.
- Cleaning: It can be cleaned with warm, soapy water and a soft brush. Avoid using ultrasonic cleaners if the stone has been treated.
- Storage: Store blue topaz separately from other gemstones to avoid scratching.
Turquoise
- Durability: Turquoise is relatively soft and porous, with a hardness of 5 to 6 on the Mohs scale.
- Cleaning: Clean turquoise with warm, soapy water and a soft cloth. Avoid exposing it to oils, lotions, or harsh chemicals, which can cause discoloration.
- Storage: Store turquoise in a dry, cool place to prevent it from losing moisture, which can lead to color fading.
Tanzanite
- Durability: Tanzanite is moderately durable, with a hardness of 6 to 7 on the Mohs scale.
- Cleaning: Clean tanzanite with warm, soapy water and a soft brush. Avoid exposing it to extreme heat, which can cause color fading.
- Storage: Store tanzanite separately from other gemstones to avoid scratching.
Zircon
- Durability: Zircon is relatively durable, with a hardness of 6 to 7.5 on the Mohs scale.
- Cleaning: Clean zircon with warm, soapy water and a soft brush. Avoid using ultrasonic cleaners if the stone has been heat-treated.
- Storage: Store zircon separately from other gemstones to avoid scratching.
Conclusion
December’s birthstones—blue topaz, turquoise, tanzanite, and zircon—offer a diverse and captivating selection of gemstones that reflect the month’s wintry charm and symbolic richness. Each stone has its own unique history, geological properties, and cultural significance, making them not only beautiful but also deeply meaningful.
From the ancient protective powers of turquoise to the modern elegance of tanzanite, these gemstones have been cherished for their beauty and symbolism across generations. Whether you are drawn to the durability of blue topaz, the spiritual properties of tanzanite, the brilliance of zircon, or the healing energy of turquoise, December’s birthstones offer something for everyone.
With proper care and appreciation, these gemstones can be enjoyed for a lifetime, serving as both ornamental treasures and symbols of personal significance. Whether worn as jewelry, collectibles, or personal talismans, December’s birthstones continue to captivate and inspire.