December, the final month of the year, is not only a time of celebration and reflection but also a month rich in gemstone tradition. Unlike most months that are associated with a single birthstone, December is uniquely linked to four distinct gemstones: Turquoise, Tanzanite, Blue Zircon, and Blue Topaz. Each of these gemstones carries its own historical significance, geological properties, and symbolic meaning, making December one of the most diverse and fascinating months in the birthstone calendar.
This article explores the origins, properties, and cultural meanings of these four December birthstones, providing a comprehensive overview for gemstone enthusiasts, jewelry buyers, and students of gemology. The information presented is based on historical records, gemological data, and contemporary industry standards, with a focus on accuracy and clarity.
Introduction
The tradition of assigning gemstones to specific months is an ancient one, with roots in Mesopotamia and the biblical references to Aaron’s Breastplate. Over time, this tradition evolved, particularly in the 20th century, as new gemstones were discovered and incorporated into the birthstone calendar for practical and commercial reasons. December, in particular, stands out for having four officially recognized birthstones, a distinction that reflects both historical practice and modern adaptations.
The December birthstones—Turquoise, Tanzanite, Blue Zircon, and Blue Topaz—are all characterized by their blue hues, a nod to the cool tones of winter and the calmness associated with the season. These gemstones have been used in jewelry for centuries, often imbued with symbolic meanings such as protection, transformation, clarity, and wisdom.
This article will delve into the history and lore, geological formation and sources, gemological properties, symbolism and metaphysical beliefs, and care and maintenance of these four December birthstones. Each section is informed by data from authoritative and widely accepted sources, ensuring a factual and reliable presentation.
History and Lore
The association of gemstones with months of the year has a long and varied history. One of the earliest known references dates back to ancient Mesopotamia, where priests wore sacred stones corresponding to different parts of the year. This tradition later influenced the Jewish High Priest’s Breastplate, described in the Book of Exodus, which featured 12 gemstones—though their exact identities remain debated.
By the 14th century, the birthstone tradition had taken a more recognizable form in Europe, where gemstones were associated with the zodiac signs and months of the year. This practice continued to evolve in the 20th century, particularly in the United States, where the Jewelers of America (now the Jewelers of America Association) played a key role in standardizing the list of birthstones.
December’s birthstone list has undergone several changes over time. Originally, only Turquoise and Zircon were considered December’s gemstones. In 1912, the National Association of Jewelers standardized an unofficial American birthstone list, and in 1952, the Jewelry Industry Council of America added Zircon to the December list. Finally, in 2002, Tanzanite was officially recognized as a December birthstone, making it the most recent addition to the birthstone calendar.
The inclusion of multiple gemstones for December is thought to have been driven by practical and commercial considerations. By offering a variety of options, the jewelry industry could cater to different tastes, budgets, and preferences. The addition of Blue Topaz in more modern times further expanded these options, making December one of the most versatile months in the birthstone tradition.
Geological Formation and Sources
Each of the four December birthstones has its own unique geological formation process and geographic origin.
Turquoise
Turquoise is a phosphate mineral formed through the weathering of copper-bearing rocks, particularly in arid regions. It is typically found in limestone deposits and forms when copper-rich water reacts with aluminum and phosphorus in the soil. The resulting blue and green hues come from copper and iron, respectively.
Major sources of turquoise include: - Iran (historically the most important source) - United States (especially Arizona, New Mexico, and Nevada) - Tibet - Nepal - China
Turquoise is often found in matrix form, meaning it is embedded in the surrounding rock. This matrix can include black, brown, or white veins, which can enhance the stone’s appearance and value.
Tanzanite
Tanzanite is a trigonal mineral and a violet-blue variety of the zoisite family. It was first discovered in 1967 in Tanzania, near the Serengeti Plains, just a few kilometers from the Kilimanjaro mountain range. It is formed under high-pressure and high-temperature conditions, typically in metamorphic rocks.
The rarity of tanzanite is due to its geographic exclusivity—it is only found in a small area of Tanzania, making it one of the most exclusive gemstones in the world. The gemstone was discovered in 1967 and was officially recognized as a birthstone in 2002, making it the youngest of all birthstones.
Blue Zircon
Zircon is a zirconium silicate that occurs in a variety of colors, including blue, yellow, red, and green. The blue variety, known as Blue Zircon, is particularly popular and is often used in jewelry. It is created through heat treatment of the naturally occurring brown or red zircon.
Blue Zircon is found in several countries, including: - Sri Lanka - Brazil - Madagascar - Australia
Zircon is known for its high refractive index, which gives it a sparkling appearance similar to diamond. It is also relatively durable, with a Mohs hardness of 6.5 to 7.5, making it suitable for everyday wear in the right settings.
Blue Topaz
Topaz is a silicate mineral that occurs in a range of colors, including blue, yellow, pink, and red. The blue variety, known as Blue Topaz, is created through irradiation and heat treatment of colorless or brown topaz.
Blue Topaz is found in several countries, including: - Brazil (the largest source) - Mexico - Nigeria - United States - Sri Lanka
It is the hardest of the December birthstones, with a Mohs hardness of 8, making it very durable and suitable for everyday wear. In 1965, Blue Topaz was designated as the official state gem of Texas, further cementing its status in the gemstone world.
Gemological Properties
Each of the four December birthstones has unique physical and optical properties that make them suitable for jewelry and personal adornment.
Turquoise
| Property | Value |
|---|---|
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O |
| Crystal System | Trigonal |
| Color | Blue, greenish-blue, green |
| Hardness (Mohs) | 5 – 6 |
| Refractive Index | 1.61 – 1.65 |
| Luster | Waxy to greasy |
| Transparency | Opaque to translucent |
| Specific Gravity | 2.60 – 2.85 |
| Cleavage | None |
| Fracture | Conchoidal |
Turquoise is a soft, porous stone that is often treated with resin or oil to enhance its durability and luster. It is not suitable for high-stress settings and requires gentle handling.
Tanzanite
| Property | Value |
|---|---|
| Chemical Formula | Ca₂Al₃(SiO₄)(OH)₃·(OH) |
| Crystal System | Trigonal |
| Color | Violet-blue, blue, purple |
| Hardness (Mohs) | 6 – 7 |
| Refractive Index | 1.694 – 1.701 |
| Luster | Vitreous |
| Transparency | Transparent to translucent |
| Specific Gravity | 3.10 – 3.40 |
| Cleavage | Perfect |
| Fracture | Uneven to conchoidal |
Tanzanite is highly prized for its color, which changes under different lighting conditions. It is relatively soft and has perfect cleavage, so it requires careful handling and secure settings.
Blue Zircon
| Property | Value |
|---|---|
| Chemical Formula | ZrSiO₄ |
| Crystal System | Tetragonal |
| Color | Blue (after heat treatment), yellow, red |
| Hardness (Mohs) | 6.5 – 7.5 |
| Refractive Index | 1.92 – 2.00 |
| Luster | Vitreous |
| Transparency | Transparent to translucent |
| Specific Gravity | 4.60 – 4.70 |
| Cleavage | None |
| Fracture | Uneven to conchoidal |
Blue Zircon is known for its high refractive index and sparkling appearance, making it a popular alternative to diamond. It is durable enough for everyday wear when properly set.
Blue Topaz
| Property | Value |
|---|---|
| Chemical Formula | Al₂SiO₄(F,OH)₂ |
| Crystal System | Orthorhombic |
| Color | Blue (after irradiation), colorless, yellow |
| Hardness (Mohs) | 8 |
| Refractive Index | 1.616 – 1.627 |
| Luster | Vitreous |
| Transparency | Transparent to translucent |
| Specific Gravity | 3.53 – 3.54 |
| Cleavage | Perfect in one direction |
| Fracture | Uneven to conchoidal |
Blue Topaz is the hardest of the four December birthstones, making it ideal for everyday wear. It is also relatively affordable, which has contributed to its popularity in the jewelry market.
Symbolism and Metaphysical Beliefs
Each of the December birthstones has been associated with symbolic meanings and metaphysical properties across different cultures and eras.
Turquoise
Turquoise has been revered for thousands of years for its protective and calming properties. In ancient Egypt, it was believed to bring good fortune and protection to the wearer. Native American cultures, particularly the Navajo and Zuni, consider turquoise a sacred stone representing healing, protection, and spiritual connection.
Modern metaphysical beliefs associate turquoise with truth, communication, and emotional balance. It is often used in meditation and healing practices to promote calmness and clarity of thought.
Tanzanite
Tanzanite is associated with transformation, intuition, and emotional healing. Its shifting colors under different lighting symbolize the ability to adapt and evolve. In modern crystal healing, tanzanite is believed to enhance spiritual awareness, open the heart, and encourage self-acceptance.
It is also considered a stone of intuition, helping the wearer access deeper emotional truths and overcome emotional blockages.
Blue Zircon
Zircon, especially in its blue form, has long been associated with wisdom, clarity, and balance. In ancient times, zircon was believed to ward off nightmares and bring prosperity. It was also thought to enhance mental clarity and promote good judgment.
Modern metaphysical practices associate zircon with inner peace, emotional stability, and spiritual growth. It is believed to help the wearer connect with their inner self and gain a deeper understanding of their life path.
Blue Topaz
Blue Topaz is associated with calmness, serenity, and emotional healing. In ancient times, it was believed to ward off evil and promote honesty. In modern crystal healing, blue topaz is used to soothe the mind, relieve stress, and encourage emotional balance.
It is also believed to enhance communication, helping the wearer express their thoughts and feelings more clearly and foster harmonious relationships.
Care and Cleaning
Proper care and cleaning are essential to maintaining the beauty and longevity of December birthstone jewelry. The specific care instructions vary depending on the gemstone's hardness, porosity, and sensitivity to chemicals.
Turquoise
Turquoise is a soft and porous stone that is highly sensitive to water, oils, and chemicals. It should be stored in a dry, cool place and avoided contact with moisture. Cleaning should be done with a soft cloth and mild soap, avoiding submersion in water or the use of ultrasonic or steam cleaners.
Tanzanite
Tanzanite is relatively soft and has perfect cleavage, so it requires careful handling. It should be stored separately from harder gemstones to avoid scratching. Cleaning should be done with warm, soapy water and a soft brush, avoiding ultrasonic cleaners due to the risk of cleavage damage.
Blue Zircon
Blue Zircon is durable enough for everyday wear, but it should still be handled with care to avoid chipping or cracking. It can be cleaned with warm, soapy water and a soft cloth or brush. Ultrasonic cleaners are generally safe, but caution is advised if the stone has been heat-treated.
Blue Topaz
Blue Topaz is the hardest of the four December birthstones, making it ideal for everyday wear. It can be cleaned with warm, soapy water and a soft brush or cloth. Ultrasonic and steam cleaners are generally safe, making it one of the easiest December birthstones to maintain.
Conclusion
December stands out in the world of birthstones as the only month with four officially recognized gemstones: Turquoise, Tanzanite, Blue Zircon, and Blue Topaz. Each of these gemstones has a rich history, distinctive gemological properties, and unique symbolic meanings, making them ideal for jewelry, personal adornment, and spiritual practices.
The inclusion of multiple gemstones for December reflects the evolving nature of the birthstone tradition, shaped by historical practice, new discoveries, and commercial demand. These gemstones offer a variety of colors, durability levels, and price points, making them accessible and appealing to a wide range of jewelry lovers.
Whether you are drawn to the healing properties of turquoise, the rare beauty of tanzanite, the sparkling brilliance of blue zircon, or the calming presence of blue topaz, December’s birthstones offer something for everyone. By understanding their history, properties, and care requirements, you can make an informed and meaningful choice when selecting December birthstone jewelry.