December is a month rich in symbolism and natural beauty, and its association with a diverse array of blue-hued gemstones reflects the multifaceted character of those born during the winter season. While many months are represented by a single birthstone, December is unique in that it is linked to five distinct gemstones—turquoise, tanzanite, blue zircon, blue topaz, and lapis lazuli—each with its own geological origins, historical significance, and symbolic meaning. What unites these gems is their association with the color blue, a hue that evokes serenity, wisdom, and the vastness of the sky and ocean.
This article explores the scientific properties, historical usage, and cultural symbolism of each of December’s official birthstones, drawing from authoritative sources to present a comprehensive overview. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, this guide will provide you with an in-depth understanding of the blue stones that mark the end of the calendar year.
History and Lore of December Birthstones
The tradition of birthstones is ancient, with roots in biblical and medieval times. The earliest known reference to birthstones appears in the Book of Exodus, which describes the twelve gemstones set in the High Priest’s breastplate. Over time, these stones became associated with specific months, and the practice of wearing a birthstone for one’s month of birth gained popularity in the 19th and 20th centuries, particularly with the formalization of the modern birthstone list by jewelers and gemological institutions.
December, in particular, has a rich tapestry of gemstones tied to it, many of which have been cherished for centuries. Turquoise, for example, has been used since ancient Egypt, where it was believed to bring protection and good fortune. Pharaohs and nobles adorned themselves with turquoise jewelry, and the stone was even used in burial rites.
Lapis lazuli, another traditional December gemstone, has been prized since antiquity for its deep blue color and golden flecks of pyrite. It was used in Mesopotamia, Egypt, and Mesoamerica, often as a symbol of wisdom and truth. Zircon, known in ancient times as “hyacinth,” has also been a popular gemstone for millennia and was even used in the 18th-century Crown Jewels of the United Kingdom.
The 20th century saw the addition of new December birthstones, including tanzanite and blue topaz, which brought fresh colors and meanings to the month. Tanzanite, discovered in the 1960s in Tanzania, is one of the rarest gems on Earth and is prized for its deep blue to violet hues. Blue topaz, while not traditionally classified as a December stone, was added to the list in more recent years due to its serene blue color and affordability, making it a popular choice for jewelry.
Geological Formation and Sources of December Birthstones
Each December birthstone has a unique geological origin and is found in specific parts of the world. Understanding these origins helps to appreciate the rarity and beauty of each gem.
Turquoise
Turquoise is a phosphate mineral formed through the interaction of copper-rich groundwater with the surrounding rock, typically in arid regions. The blue-green color comes from the presence of copper, while the greenish tones are due to iron. The veins and patterns visible in turquoise, known as matrix, are remnants of the rock in which it formed.
Historically, Persia (modern-day Iran) was the primary source of turquoise, but today, Nevada in the United States, Iran, China, and Egypt are major producers. The Nevada source is particularly famous for its intense blue color and minimal matrix.
Tanzanite
Tanzanite is a trigonal mineral and a cubic zirconium variety of the cassiterite mineral. It was first discovered in the 1960s near Mount Kilimanjaro in Tanzania, from which it takes its name. Tanzanite is notable for its trichroism, meaning it can display three different colors—blue, violet, and brown—depending on the angle of light. The blue to violet hues are the most prized and are the reason tanzanite became a popular gemstone.
Due to its limited source, tanzanite is considered one of the most rare gemstones in the world. It is estimated that all the tanzanite that will ever be available has already been found, making it a gem of increasing value.
Blue Zircon
Zircon is a zirconium silicate that occurs in various colors, including red, yellow, brown, and blue. Blue zircon is created through heat treatment, which transforms the natural brown or yellow color into a vibrant blue. This process has been used for centuries, and zircon has been known in ancient times under names like “hyacinth.”
Zircon is found in many parts of the world, including Australia, Sri Lanka, Thailand, and Brazil. The blue zircon used in jewelry is typically sourced from Australia and Sri Lanka, where large deposits of zircon are found.
Blue Topaz
Topaz is a silicate mineral that occurs in a range of colors, including yellow, pink, and blue. Blue topaz is the most popular variety and is created through irradiation and heat treatment, which alters the natural color of the stone. The blue color is typically a calm, serene blue, similar to the sky or sea.
Blue topaz is widely available, with major sources in Brazil, Mexico, and Nigeria. It is one of the most affordable December birthstones, making it a popular choice for everyday jewelry.
Lapis Lazuli
Lapis lazuli is a metamorphic rock composed primarily of lazurite, a deep blue mineral, along with pyrite (which gives it its golden flecks) and calcite. It forms under high-pressure conditions, typically in regions where shale is subjected to heat and pressure.
The primary source of lapis lazuli is Afghanistan, where it has been mined for thousands of years. Other sources include Russia, Canada, and the United States, but Afghanistan remains the most significant and highest-quality source.
Gemological Properties of December Birthstones
Each of December’s birthstones has unique gemological properties that influence its use in jewelry and its care requirements. Below is a table summarizing the key gemological characteristics of each stone:
| Gemstone | Color | Hardness (Mohs) | Refractive Index | Chemical Composition | Transparency | Luster | Cleavage |
|---|---|---|---|---|---|---|---|
| Turquoise | Blue, green | 5–6 | 1.60–1.65 | Hydrated phosphate of aluminum | Opaque | Waxy to greasy | Indistinct |
| Tanzanite | Blue, violet | 6–7 | 1.694–1.699 | Calcium aluminum silicate | Translucent to transparent | Vitreous | Perfect in three directions |
| Blue Zircon | Blue | 6–7.5 | 1.92–2.00 | Zirconium silicate | Translucent to transparent | Vitreous | Perfect in one direction |
| Blue Topaz | Blue | 8 | 1.61–1.63 | Aluminum silicate | Transparent | Vitreous | None |
| Lapis Lazuli | Blue with golden flecks | 5–6 | 1.62–1.64 | Lazurite, pyrite, calcite | Opaque | Waxy to greasy | Indistinct |
Turquoise
- Hardness: 5–6
- Color: Ranges from blue to green, often with a matrix pattern.
- Transparency: Opaque
- Luster: Waxy to greasy
- Cleavage: Indistinct
- Refractive Index: 1.60–1.65
Turquoise is relatively soft and porous, which makes it sensitive to heat, chemicals, and acidic substances. It is often stabilized or treated with resins to improve durability.
Tanzanite
- Hardness: 6–7
- Color: Blue to violet
- Transparency: Translucent to transparent
- Luster: Vitreous
- Cleavage: Perfect in three directions
- Refractive Index: 1.694–1.699
Tanzanite is trichroic, meaning it can display three different colors depending on the angle of light. Its perfect cleavage makes it prone to chipping or breaking if not set carefully.
Blue Zircon
- Hardness: 6–7.5
- Color: Blue (created by heat treatment)
- Transparency: Translucent to transparent
- Luster: Vitreous
- Cleavage: Perfect in one direction
- Refractive Index: 1.92–2.00
Zircon has a high refractive index, giving it a sparkling, fire-like brilliance. Its cleavage makes it fragile, so it requires careful handling in jewelry settings.
Blue Topaz
- Hardness: 8
- Color: Blue (created by irradiation and heat treatment)
- Transparency: Transparent
- Luster: Vitreous
- Cleavage: None
- Refractive Index: 1.61–1.63
Blue topaz is very durable, making it ideal for everyday wear. It has a high luster and is relatively affordable, which contributes to its popularity.
Lapis Lazuli
- Hardness: 5–6
- Color: Deep blue with golden flecks of pyrite
- Transparency: Opaque
- Luster: Waxy to greasy
- Cleavage: Indistinct
- Refractive Index: 1.62–1.64
Lapis lazuli is opaque and is often carved or polished to a smooth finish. It is porous and can be sensitive to oils and lotions.
Symbolism and Metaphysical Beliefs
Each December birthstone carries its own symbolic meaning and metaphysical properties, which have been passed down through various cultures and eras.
Turquoise
- Symbolism: Success, happiness, prosperity
- Metaphysical Beliefs: Turquoise is believed to bring good fortune and protection, particularly in ancient cultures. It was thought to guarantee health and well-being and was used in protective amulets. In some cultures, it was believed that turquoise would break into pieces before a disaster, acting as a warning.
Tanzanite
- Symbolism: Uniqueness, rarity
- Metaphysical Beliefs: Tanzanite is associated with spiritual awakening and emotional healing. It is believed to enhance intuition and promote inner peace. Due to its limited availability, it is also seen as a stone of exclusivity and rarity.
Blue Zircon
- Symbolism: Clarity, wisdom
- Metaphysical Beliefs: Zircon is considered a stone of clarity and truth. It is believed to enhance concentration and mental clarity, making it useful for studying or meditation. It is also thought to protect against negative energies.
Blue Topaz
- Symbolism: Calm, serenity
- Metaphysical Beliefs: Blue topaz is associated with calmness and emotional balance. It is believed to soothe the mind and reduce stress, making it a popular stone for those seeking inner peace.
Lapis Lazuli
- Symbolism: Wisdom, truth, royalty
- Metaphysical Beliefs: Lapis lazuli has long been associated with wisdom and enlightenment. In ancient times, it was believed to enhance intellectual abilities and was used by scholars and mystics. It is also considered a stone of truth, promoting honesty and integrity.
Care and Cleaning of December Birthstones
Proper care is essential to maintain the beauty and longevity of any gemstone. Each of December’s birthstones has specific care requirements based on its hardness, porosity, and sensitivity to chemicals or heat.
Turquoise
- Avoid: Heat, direct sunlight, and chemicals such as acids, perfumes, and lotions
- Cleaning: Use warm, soapy water and a soft cloth. Do not use ultrasonic cleaners or steamers.
- Storage: Store separately from other gems to prevent scratches.
Tanzanite
- Avoid: Exposure to sharp impacts due to perfect cleavage
- Cleaning: Use mild soap and water. Avoid harsh chemicals and abrasive cleaners
- Storage: Store in a soft pouch to prevent damage.
Blue Zircon
- Avoid: Exposure to heat or sharp blows
- Cleaning: Use mild soap and water. Avoid ultrasonic cleaners due to cleavage
- Storage: Store in a secure, padded container
Blue Topaz
- Avoid: No special care required due to high hardness
- Cleaning: Can be cleaned with steam or ultrasonic cleaners
- Storage: Store with other durable gems
Lapis Lazuli
- Avoid: Oils, lotions, and acidic substances
- Cleaning: Use warm, soapy water. Avoid abrasive cleaners
- Storage: Store separately from other gems to prevent scratches
Conclusion
December’s birthstones offer a rich and diverse palette of blue hues, each with its own unique geological origin, historical significance, and symbolic meaning. From the ancient allure of turquoise and lapis lazuli to the modern rarity of tanzanite and blue topaz, these gems reflect the complexity and beauty of the winter season.
Whether you are drawn to the protective powers of turquoise, the spiritual clarity of zircon, or the rare elegance of tanzanite, each December birthstone has a story to tell. Understanding their properties, care requirements, and cultural significance allows you to appreciate these gems not just as jewelry, but as pieces of history and symbolism.
For those born in December, or those seeking a meaningful gift, these blue gems offer a versatile and beautiful choice, combining aesthetic appeal with deep-rooted tradition.