December, the final month of the year, is distinguished by a captivating array of blue gemstones that reflect the cool serenity and festive spirit of winter. Known for its three official birthstones—Tanzanite, Turquoise, and Blue Zircon—along with Blue Topaz and Lapis Lazuli as traditional or alternative options, December offers a unique and diverse color palette. These stones, each with its own distinct properties and historical significance, not only add beauty to jewelry but also carry rich symbolism and cultural importance.
This article delves into the gemological properties, historical background, cultural symbolism, and practical care of these December birthstones. By exploring the blue hues that define this month, we uncover the story behind each stone and its enduring appeal in both historical and modern contexts.
History and Lore
The tradition of birthstones dates back to ancient times, with roots in religious and cultural practices. The earliest known record of birthstones can be traced to the Breastplate of Aaron, mentioned in the Hebrew Bible, where twelve gemstones represented the twelve tribes of Israel. Over time, these stones became associated with the months of the year, forming the basis of the modern birthstone calendar.
For December, the birthstone tradition has evolved to include multiple gemstones, reflecting the month's unique position at the end of the year. Turquoise, one of the oldest and most revered gemstones, has been used in jewelry since ancient times. It was particularly valued in ancient Egypt, where it was believed to have protective and healing properties. The name "Turquoise" comes from the French pierre turquoise, meaning "Turkish stone," as it was introduced to Europe through trade routes from the East.
Tanzanite, by contrast, is a relatively modern discovery. Found in the 1960s in Tanzania, this gemstone quickly became a symbol of the 20th century. Its unique violet-blue color and pleochroic nature—where it displays different colors depending on the viewing angle—make it a standout among December's birthstones. Tanzanite is also notable for being one of the rarest gemstones, as it is found only in one location near Mount Kilimanjaro.
Zircon, another ancient gemstone, has been used in jewelry for over 2,000 years. It is known for its brilliance and refractive qualities, often compared to diamonds. Zircon is also one of the oldest minerals on Earth, with some crystals dating back over 4 billion years. This historical depth adds to its allure as a December birthstone.
Blue Topaz and Lapis Lazuli also hold significant historical and cultural importance. Blue Topaz, often created through heat treatment, has become a popular alternative to natural blue gems. Lapis Lazuli, a metamorphic rock, has been used in ancient art and jewelry and was highly prized by the Egyptians, who used it to create decorative items and even ground it into pigment for painting.
The inclusion of multiple birthstones for December reflects not only the diversity of gemstones available but also the flexibility of the birthstone tradition. It allows individuals to choose a stone that best aligns with their personal preferences, budget, and the symbolic meaning they associate with the gem.
Geological Formation and Sources
Each of December’s birthstones has a unique geological origin and source, contributing to its rarity, beauty, and value.
Tanzanite is a variety of the mineral zoisite and was first discovered in 1967 in the Merelani Hills of northern Tanzania. This gemstone is formed when zoisite undergoes heat treatment, which enhances its blue and violet hues. What makes Tanzanite particularly unique is its limited source—no other deposits of this gemstone exist anywhere in the world. This exclusivity contributes to its high value and the fact that it is considered one of the rarest gemstones in the world.
Turquoise is an opaque mineral composed of basic copper and aluminum phosphate. It forms in arid regions where copper-rich groundwater seeps into the rock, reacting with other minerals to create its signature blue-green color. The veins and patterns seen in turquoise—often referred to as the matrix—are caused by the surrounding rock and can vary greatly in appearance. Major sources of turquoise include the United States (particularly Arizona and Nevada), Iran, China, and Egypt.
Zircon is a zirconium silicate mineral that occurs in a wide range of colors, including blue, yellow, red, and green. Blue zircon is especially popular and is often heat-treated to enhance its color. Zircon is found in various parts of the world, including Australia, Sri Lanka, Thailand, and Brazil. Some of the oldest zircon crystals discovered are over 4 billion years old, making it one of the oldest known minerals on Earth.
Blue Topaz is typically colorless in its natural state but is often treated with heat or radiation to produce its blue color. Natural blue topaz is rare, so most blue topaz used in jewelry is enhanced. The treatment process does not affect the gemstone's durability or value. Topaz is found in several countries, including Brazil, Mexico, and the United States.
Lapis Lazuli is a metamorphic rock composed primarily of lazurite, along with other minerals such as pyrite and calcite. It forms under high pressure and temperature conditions deep within the Earth's crust. The most famous source of lapis lazuli is Afghanistan, where it has been mined for thousands of years. Other sources include Russia, Chile, and Canada.
The geological processes that create these gemstones are as varied as their colors and properties. Each stone tells a story of the Earth’s history, from the ancient formations of zircon to the rare and fleeting deposits of tanzanite. Understanding these origins not only adds to the appreciation of the gemstone’s beauty but also highlights the natural forces that shape our planet.
Gemological Properties
Each of December’s birthstones possesses distinct gemological properties that contribute to its allure and utility in jewelry.
Tanzanite
- Chemical Formula: Ca₂Al₃(SiO₄)(OH)₃·(OH) or simply CaAl₃(SiO₄)(OH)₃ when simplified
- Hardness (Mohs Scale): 6 to 7
- Color: Violet-blue, with pleochroism that allows it to display blue, violet, or burgundy depending on the viewing angle
- Refractive Index: 1.694 to 1.700
- Specific Gravity: 3.10 to 3.38
- Crystal System: Monoclinic
- Transparency: Transparent to translucent
- Luster: Vitreous
- Cleavage: Perfect in one direction
- Luminescence: Some tanzanite exhibits weak phosphorescence
Tanzanite's pleochroism is one of its most distinctive features, making it a favorite among gemologists and collectors. Its relatively low hardness compared to other gemstones means it requires careful handling to prevent scratches and chips.
Turquoise
- Chemical Formula: CuAl₆(PO₄)₄(OH)₈·4H₂O
- Hardness (Mohs Scale): 5 to 6
- Color: Blue to green, with variations depending on the presence of copper and iron
- Refractive Index: 1.61 to 1.65
- Specific Gravity: 2.6 to 2.8
- Crystal System: Trigonal
- Transparency: Opaque
- Luster: Waxy to greasy
- Cleavage: None
- Luminescence: Weak
Turquoise is an opaque mineral with a waxy luster that gives it a unique appearance. Its hardness is relatively low, which means it is susceptible to scratches and should be handled with care. The presence of matrix—dark veins or patterns—adds to its character and can affect its value.
Zircon
- Chemical Formula: ZrSiO₄
- Hardness (Mohs Scale): 6.5 to 7.5
- Color: Available in many colors, with blue being the most popular
- Refractive Index: 1.92 to 2.00
- Specific Gravity: 4.6 to 4.7
- Crystal System: Tetragonal
- Transparency: Transparent to translucent
- Luster: Vitreous
- Cleavage: None
- Luminescence: Some zircon exhibits strong luminescence under ultraviolet light
Blue zircon is known for its high refractive index, which gives it a brilliant sparkle. Its hardness is higher than that of tanzanite and turquoise, making it more durable. However, zircon is sensitive to heat and can change color or become damaged if exposed to high temperatures.
Blue Topaz
- Chemical Formula: Al₂SiO₄(F,OH)₂
- Hardness (Mohs Scale): 8
- Color: Blue (naturally rare, often enhanced)
- Refractive Index: 1.62 to 1.64
- Specific Gravity: 3.4 to 3.6
- Crystal System: Hexagonal
- Transparency: Transparent
- Luster: Vitreous
- Cleavage: Perfect
- Luminescence: Weak
Blue topaz is a durable gemstone with a hardness of 8, making it suitable for everyday wear. Its blue color is often enhanced through heat treatment, which does not affect its durability or value. Topaz is also known for its excellent clarity and brilliance.
Lapis Lazuli
- Chemical Composition: A metamorphic rock composed primarily of lazurite (a sulfide mineral), with pyrite and calcite
- Hardness (Mohs Scale): 5 to 6
- Color: Deep blue with flecks of gold (pyrite)
- Refractive Index: Varies depending on composition
- Specific Gravity: 2.4 to 2.9
- Transparency: Opaque
- Luster: Waxy to greasy
- Cleavage: None
Lapis lazuli is a composite rock rather than a single mineral, which gives it a unique appearance. Its deep blue color with golden flecks makes it a popular choice for decorative items and jewelry. It is relatively soft and opaque, requiring careful handling to avoid scratches.
The gemological properties of these stones not only define their physical characteristics but also influence their use in jewelry and their care requirements. Each gemstone has its own strengths and vulnerabilities, which must be considered when selecting and maintaining December birthstone jewelry.
Symbolism and Metaphysical Beliefs
The symbolism and metaphysical properties associated with December’s birthstones add another layer of meaning to these gemstones, making them more than just beautiful objects but also powerful symbols in various cultures and traditions.
Tanzanite is often associated with transformation, spiritual growth, and emotional healing. Its violet-blue color is thought to represent the transition between the material and spiritual worlds. In metaphysical traditions, tanzanite is believed to enhance intuition and facilitate communication with higher realms. It is also said to help individuals release emotional blockages and foster a sense of peace and balance.
Turquoise has long been regarded as a stone of protection and good fortune. In ancient cultures, it was believed to ward off negative energies and bring prosperity. It is also associated with wisdom, clarity, and the ability to express oneself. Turquoise is often used in meditation to promote a calm and focused mind. Its blue-green color is seen as a bridge between the earth and the sky, representing the connection between the physical and spiritual worlds.
Zircon, particularly blue zircon, is known for its vibrant energy and is often associated with vitality and renewal. It is believed to enhance mental clarity, stimulate creativity, and promote emotional stability. Zircon is also considered a stone of time, reflecting its ancient origins and the idea that it has witnessed the passage of eons. In some traditions, zircon is used to enhance the power of other gemstones and to amplify their energies.
Blue Topaz is associated with calmness, serenity, and the ability to see the bigger picture. It is believed to help individuals release stress and anxiety, promoting a sense of peace and tranquility. Blue topaz is also thought to enhance communication and encourage honest expression. Its cool blue color is said to resonate with the throat chakra, supporting clear and effective communication.
Lapis Lazuli is one of the most spiritually powerful gemstones, often associated with wisdom, truth, and spiritual enlightenment. It is believed to enhance intellectual ability, stimulate the mind, and promote a deeper understanding of the self. Lapis lazuli is also associated with the third eye chakra, which is believed to govern intuition and spiritual insight. Its golden flecks of pyrite are seen as symbols of the sun and the power of transformation.
These metaphysical beliefs, while not scientifically proven, are an essential part of the cultural and historical significance of these gemstones. They add to the allure of December’s birthstones, making them not only beautiful but also meaningful and symbolic in various traditions.
Care and Cleaning
Proper care and cleaning are essential for maintaining the beauty and longevity of December’s birthstones. Each gemstone has specific needs due to its unique physical properties, and understanding these can help ensure that your jewelry remains in excellent condition.
Tanzanite should be cleaned gently to avoid damaging its relatively low hardness and perfect cleavage. Use a soft cloth and warm, soapy water to clean it, avoiding ultrasonic cleaners and steamers, which can cause damage. Tanzanite should also be stored separately from harder gemstones to prevent scratches.
Turquoise is an opaque gemstone that is sensitive to harsh chemicals and extreme temperatures. It should be cleaned with a soft cloth and mild soap and water. Avoid exposing it to acidic substances, as they can cause discoloration. Turquoise should also be stored in a dry place, as excessive moisture can cause it to crack or lose its luster.
Zircon, particularly blue zircon, is relatively durable but still requires careful handling. It can be cleaned with a soft cloth and warm, soapy water, and ultrasonic cleaners can be used cautiously. Zircon should be stored away from harder gemstones to prevent scratches and should be kept in a dry environment to avoid any changes in color.
Blue Topaz is one of the most durable December birthstones, with a hardness of 8 on the Mohs scale. It can be cleaned with a soft cloth and warm, soapy water or with an ultrasonic cleaner. However, it should not be exposed to high heat, as this can cause it to lose its color.
Lapis Lazuli is a composite rock that is relatively soft and should be handled with care. It should be cleaned with a soft cloth and mild soap and water, avoiding harsh chemicals and abrasive materials. Lapis lazuli should be stored in a dry place to prevent moisture-related damage.
By following these care and cleaning guidelines, you can ensure that your December birthstone jewelry remains beautiful and valuable for years to come.
Conclusion
December’s birthstones—Tanzanite, Turquoise, Blue Zircon, Blue Topaz, and Lapis Lazuli—each bring their own unique beauty and symbolism to the month. From the rare and vibrant violet-blue of Tanzanite to the ancient blue-green of Turquoise and the brilliant clarity of Zircon, these gemstones reflect the cool serenity and festive spirit of winter. Their geological origins, historical significance, and metaphysical properties make them not only valuable in jewelry but also meaningful in cultural and spiritual contexts.
Understanding the properties and care requirements of these gemstones allows for the appreciation of their beauty and durability. Whether chosen for their color, history, or symbolism, December’s birthstones offer a rich and diverse palette that continues to captivate gemstone enthusiasts and jewelry lovers alike.