December is one of the few months in the calendar year to boast not one, but three official birthstones: tanzanite, turquoise, and zircon (particularly blue zircon). This multiplicity is not an anomaly but a reflection of the evolving nature of birthstone traditions, shaped by cultural, commercial, and geological discoveries over centuries. Each of these gemstones carries its own distinct charm, history, and symbolism, making December a particularly rich and fascinating month in the world of gemology.
This article explores the gemological properties, historical significance, cultural lore, and modern relevance of the December birthstones. Drawing from authoritative sources and centuries of tradition, we present a comprehensive overview of these stones, their origins, and the meanings they hold across time and cultures.
Introduction
December birthstones reflect the month’s dual themes of transition and celebration. From the arrival of the winter solstice to the culmination of year-end festivities, the month is steeped in symbolic meaning. The three gemstones associated with December—tanzanite, turquoise, and zircon—each tell a unique story, rooted in ancient traditions and refined by modern gemological understanding. While the concept of birthstones dates back to Biblical times, the list has evolved significantly, especially in the 20th and 21st centuries.
Turquoise, with its deep blue-green hues, has been cherished for millennia by cultures around the world. Zircon, particularly in its blue form, is an ancient gemstone that has found new life as a December symbol. Tanzanite, on the other hand, is a relatively modern discovery, first recognized in the 1960s and officially added to the December birthstone list in 2002.
This article will delve into the history, geology, symbolism, and care of each of these gemstones, offering a detailed look at their roles in both ancient and modern traditions.
Historical and Cultural Significance
Evolution of the Birthstone List
The concept of birthstones is believed to have originated in the Biblical Book of Exodus, where Aaron’s breastplate was adorned with twelve stones representing the twelve tribes of Israel. Over time, these stones were associated with the months of the year, and the tradition was adopted and adapted by various cultures.
In the case of December, the earliest references point to Ruby as the December birthstone. However, by the 19th and 20th centuries, the list had evolved significantly. The modern list of December birthstones has seen several changes:
- 1870: Turquoise was designated as a December birthstone in a pamphlet by Tiffany & Co. titled Gregorian Birthstone Poems.
- 1912: The National Association of Jewellers (now the Jewellers of America) listed turquoise as the primary December birthstone and lapis lazuli as an alternative.
- 1952: The Jewelry Industry Council of America added zircon to the list, replacing lapis lazuli.
- 2002: Tanzanite was officially recognized as a December birthstone by the American Gem Trade Association (AGTA).
This fluidity in the list reflects the dynamic nature of gemstone popularity and the influence of commercial and cultural trends on birthstone traditions.
The Three December Birthstones
1. Turquoise
Turquoise has been a symbol of protection, prosperity, and good fortune for thousands of years. It is one of the oldest known gemstones, with evidence of its use dating back to 5,000 BCE in Egypt, where it was used in jewelry and amulets.
In ancient Egypt, turquoise was associated with the gods and was believed to offer divine protection. The pharaohs wore it to signify power and connection to the heavens. In China, turquoise was carved into intricate objects and used in ceremonies. In Native American cultures, particularly among the Navajo and Hopi, turquoise is considered a sacred stone that brings healing and balance.
In more recent times, Hindu mystics associated turquoise with the zodiac sign Sagittarius, which spans from November 21 to December 21, and believed that seeing turquoise after the new moon could bring wealth.
2. Zircon
Zircon has been a gemstone of great antiquity, with some specimens dating back 4.4 billion years, making them the oldest known minerals on Earth. These ancient zircons were crucial in the development of radiometric dating, a scientific method used to determine the age of rocks and minerals.
Blue zircon, in particular, has been a popular choice as a December birthstone since the mid-20th century. It is known for its high refractive index, which gives it a brilliant, fire-like sparkle. Unlike cubic zirconia (a synthetic diamond simulant), natural zircon is a genuine gemstone found in various parts of the world, including Thailand, Cambodia, and Vietnam.
In ancient traditions, zircon was believed to bring wisdom and divine favor. Some sources suggest that zircon was used in Tibetan and Hindu practices for its protective and calming properties.
3. Tanzanite
Tanzanite is the youngest of the December birthstones, having been discovered in 1967 in the foothills of Mount Kilimanjaro, Tanzania. It was initially referred to as blue zoisite but was renamed tanzanite to honor its country of origin.
Tanzanite quickly gained popularity due to its vivid blue-violet color and strong pleochroism, meaning it can display different colors depending on the angle of light. Tiffany & Co. played a major role in promoting the stone, emphasizing its rarity and connection to Tanzania, where it is the only place in the world it can be found.
Tanzanite is believed to have soothing and protective qualities, making it a favorite in spiritual and holistic practices. It is also associated with emotional balance and spiritual communication, encouraging the wearer to express themselves with clarity and compassion.
Geological Formation and Sources
Turquoise
Turquoise is a phosphate mineral that forms in the oxidized zone of copper deposits, typically in arid regions. It is composed of basic aluminum phosphate and is known for its blue to green color, which comes from trace amounts of copper and iron.
Major sources of turquoise include:
- Iran (Persia) – historically the most important source for high-quality turquoise
- United States (especially Nevada and Arizona)
- China, Egypt, and Mexico
Turquoise is often found with matrix—veins of the host rock—ranging from fine, delicate lines to bold, contrasting patterns.
Zircon
Zircon is a zirconium silicate that forms in igneous rocks and is known for its high refractive index, strong dispersion, and durability. It can occur in a wide range of colors, including brown, yellow, red, green, and blue.
Blue zircon is typically created through heat treatment, a process that enhances its natural beauty and stability. This treatment is stable and permanent, making it a popular option for jewelry.
Natural zircon is found in:
- Thailand
- Cambodia
- Vietnam
- Australia
- India
- Brazil
Zircon is also known for its radioactive properties, as it often contains trace amounts of uranium and thorium. This characteristic has made it valuable in geological research, particularly in radiometric dating.
Tanzanite
Tanzanite is a trigonal mineral and a variety of cassiterite (a type of zircon). It is composed of aluminum silicate and is known for its pleochroism, a property that allows it to display multiple colors depending on the lighting and viewing angle.
The only known source of tanzanite is the Merelani Hills in northern Tanzania, near the base of Mount Kilimanjaro. The gemstone was discovered in 1967 and quickly became a commercial success due to its vivid color and rarity.
Tanzanite is heat-treated to enhance its color, turning it from a brownish or violet hue to the vibrant blue and purple tones that make it so desirable.
Gemological Properties
| Gemstone | Chemical Formula | Color | Hardness (Mohs) | Refractive Index | Transparency | Specific Gravity | Cleavage | Sources of Origin |
|---|---|---|---|---|---|---|---|---|
| Turquoise | Al₂(SO₄)₃(OH)₃·4H₂O | Blue to green | 5–6 | 1.60–1.65 | Translucent to opaque | 2.0–2.8 | No | Iran, USA, China, Egypt, Mexico |
| Zircon | ZrSiO₄ | Brown, yellow, red, green, blue | 6–7.5 | 1.92–2.01 | Transparent to translucent | 3.9–4.7 | Perfect | Thailand, Cambodia, Vietnam, Australia, India, Brazil |
| Tanzanite | ZrSiO₄ (blue variety) | Blue to violet | 6–7 | 1.69–1.70 | Transparent to translucent | 3.1–3.5 | Perfect | Tanzania (Merelani Hills) |
Turquoise
- Hardness: 5–6 on the Mohs scale
- Color: Blue to green, often with matrix patterns
- Refractive Index: 1.60–1.65
- Transparency: Translucent to opaque
- Specific Gravity: 2.0–2.8
- Cleavage: None
- Durability: Moderate, best suited for pendants and earrings rather than rings
Zircon
- Hardness: 6–7.5 on the Mohs scale
- Color: Naturally occurs in brown, yellow, red, green, and blue
- Refractive Index: 1.92–2.01
- Transparency: Transparent to translucent
- Specific Gravity: 3.9–4.7
- Cleavage: Perfect in one direction
- Durability: Good, though care should be taken with cleavage planes
- Heat Treatment: Common and permanent
Tanzanite
- Hardness: 6–7 on the Mohs scale
- Color: Blue to violet, often with pleochroism
- Refractive Index: 1.69–1.70
- Transparency: Transparent to translucent
- Specific Gravity: 3.1–3.5
- Cleavage: Perfect in one direction
- Durability: Moderate, best suited for pendants and earrings
- Heat Treatment: Common and stable
Symbolism and Metaphysical Beliefs
Turquoise
Turquoise has long been associated with protection, wisdom, and good fortune. In ancient Egypt, it was believed to ward off evil and disease. In Native American cultures, it is considered a stone of healing and spiritual balance, often used in ceremonies and rituals.
Modern metaphysical beliefs attribute calming and centering properties to turquoise. It is said to enhance communication, soothe anxiety, and promote inner peace. In Hindu traditions, turquoise is associated with Sagittarius and is believed to sharpen the mind and encourage learning.
Zircon
Zircon is known for its divine and protective qualities. In ancient traditions, it was used in ceremonial and spiritual practices to connect with higher realms. It is believed to enhance wisdom, clarity, and spiritual insight.
In modern metaphysical practices, zircon is used to align the chakras, especially the heart and crown chakras, promoting emotional balance and spiritual awareness. It is also said to protect the wearer from negative energies and encourage inner strength.
Tanzanite
Tanzanite is often referred to as a stone of transformation and spiritual growth. It is believed to facilitate emotional healing, release fear and anger, and enhance spiritual communication. In spiritual circles, it is used to connect with higher consciousness and encourage compassion and empathy.
Tanzanite is also associated with emotional balance, inner harmony, and self-expression. It is said to soothe the heart, alleviate stress, and encourage one to speak from the heart with clarity and grace.
Care and Cleaning
General Tips
All three December birthstones—tanzanite, turquoise, and zircon—require gentle care due to their moderate hardness and sensitivity to heat and chemicals.
- Avoid exposure to harsh chemicals such as household cleaners, chlorine, and acids.
- Remove jewelry before swimming, exercising, or handling chemicals.
- Store separately to avoid scratches and abrasions.
- Clean with warm, soapy water and a soft cloth or brush.
- Avoid steam cleaning or ultrasonic cleaners, as they may cause damage.
Turquoise
- Soft and porous, turquoise is especially sensitive to water, chemicals, and heat.
- Clean with a damp cloth and mild soap.
- Avoid soaking or using ultrasonic cleaners.
- Store in a dry, cool place to prevent drying and cracking.
Zircon
- Zircon is relatively durable, but cleavage planes can be a weakness.
- Avoid using ultrasonic cleaners, as they may cause cleavage or fracture.
- Clean with warm, soapy water and a soft brush.
- Avoid exposure to sudden temperature changes, as this may cause thermal shock.
Tanzanite
- Tanzanite is sensitive to heat and pressure and should be handled with care.
- Avoid exposing to direct sunlight for long periods, as this may cause color fading.
- Clean with a soft cloth and mild soap.
- Avoid using steam or ultrasonic cleaners.
Conclusion
December birthstones—tanzanite, turquoise, and zircon—represent a rich tapestry of history, beauty, and symbolism. Each gemstone carries a unique story, shaped by centuries of cultural traditions, geological discoveries, and modern appreciation.
From the ancient sacred stone of turquoise to the radiant blue zircon and the vibrant tanzanite, these gems offer more than just aesthetic appeal. They are symbols of protection, transformation, and emotional balance, making them cherished gifts and meaningful adornments.
Whether you are drawn to the deep blue of turquoise, the sparkling brilliance of zircon, or the captivating hues of tanzanite, December offers a gemstone to suit every taste, style, and occasion. As we continue to explore and appreciate these stones, we honor not only their beauty but also their enduring legacy in the world of gemology.