For those born on December 21st, the birthstone is a triad of gemstones: Tanzanite, Turquoise, and Zircon. Each of these gems carries unique beauty, history, and symbolism, making December 21st a particularly rich date in the birthstone calendar. This article delves into the geological, historical, and cultural significance of these three gemstones, drawing from authoritative sources to provide a comprehensive overview.
Introduction
December 21st falls at the end of the month and is traditionally associated with the winter solstice in the Northern Hemisphere, a time of reflection and celebration. It is also the birthstone date for three distinct gemstones: Tanzanite, Turquoise, and Zircon. While these stones differ in their chemical composition, physical properties, and historical uses, they all share a common theme of success, protection, and positive energy—traits believed to be especially meaningful for those born on this day.
This article explores the origin and formation, gemological properties, cultural and metaphysical significance, and modern uses of these three December 21st birthstones. Whether you're a gemstone enthusiast, a jewelry buyer, or simply curious about the symbolic meanings behind birthstones, this guide offers a detailed look into the world of Tanzanite, Turquoise, and Zircon.
History and Lore
Tanzanite: A Modern Discovery
Tanzanite is the newest of the three gemstones associated with December 21st. Discovered in the 1960s in Tanzania, it was first marketed as a variety of zoisite. Its discovery was made by a Tanzanian Maasai herder who found the stone and showed it to a German geologist. The stone’s vivid blue-violet color quickly made it a sensation in the gemstone world.
Tanzanite is unique in that it is only found in one location on Earth: the Merelani Hills in northern Tanzania. This exclusivity has contributed to its value and mystique. The stone was officially recognized as a birthstone in 2002 by the American Gem Trade Association (AGTA), adding it to the existing December birthstones of Turquoise and Zircon.
Turquoise: An Ancient Gem
Turquoise, on the other hand, is one of the oldest known gemstones in human history. Its name derives from the French pierre turquoise, meaning “Turkish stone,” as it was first imported to Europe through Turkey. However, the stone itself is not native to Turkey; it has been mined for thousands of years in countries such as Egypt, China, Iran, and the American Southwest.
Turquoise has been used by ancient civilizations including the Egyptians, who believed it had protective powers, and the Native American tribes of the Southwest, who used it in ceremonies and as a symbol of spiritual connection. It was also prized by the Persians and the Chinese, who crafted intricate inlays and carvings from the stone.
In medieval Europe, Turquoise was used in jewelry and amulets, and it was believed to bring good fortune, protection, and love. It was also considered a healing stone, used to treat ailments ranging from asthma to digestive issues.
Zircon: A Timeless Gem
Zircon has been used in jewelry for over 2000 years, making it one of the oldest continuously used gemstones. The name comes from the Arabic zankāfī, meaning “amber,” and was later adapted into the Persian zargun, meaning “gold color.”
Blue Zircon, in particular, is the most popular variety and is often used as a December birthstone. Zircon has been found in archaeological sites dating back to ancient Egypt and Mesopotamia. It was also used in jewelry by the Greeks and Romans, who associated it with wisdom and divine favor.
In the modern era, Zircon has been used as a diamond simulant, particularly in the 1970s and 1980s, due to its high refractive index and brilliance. However, it is now appreciated for its natural beauty and affordability.
Geological Formation and Sources
Tanzanite: A Rare and Limited Source
Tanzanite forms in metamorphic rocks, specifically in calc-silicate skarn deposits, which are created when limestone is subjected to high heat and pressure. The Merelani Hills in Tanzania, the only known source of Tanzanite, are the result of such geological activity.
The Merelani Hills were once part of the ancient Indian Ocean seabed, uplifted by tectonic activity millions of years ago. The presence of zinc, copper, and vanadium in the region contributed to the formation of Tanzanite. Its blue-violet color is due to the presence of trivalent iron (Fe³⁺), which is activated by irradiation.
Tanzanite is extremely rare, with production limited to the Merelani Hills. This rarity, combined with the stone’s beauty and the fact that it is only found in one location, makes it a highly sought-after gemstone.
Turquoise: A Mineral of Earth and Time
Turquoise is a phosphate mineral, formed by the interaction of water and copper-rich minerals. It is typically found in weathered copper deposits, where groundwater carrying copper ions seeps into the surrounding rock and reacts with phosphorus and aluminum.
The most famous sources of Turquoise include:
- Iran (Nehbandan and Kuh-e-Bafq): Known for producing some of the finest and most colorful Turquoise in the world.
- The American Southwest (Arizona, New Mexico, Nevada): Particularly known for the turquoise mined from the Cerrillos Hills and Cerrado Hills.
- China (Hunan, Guangxi): Produces a unique greenish-blue Turquoise.
- Egypt (Kabrit Deposit): Known as “Persian Turquoise,” it was used in ancient Egyptian jewelry.
Turquoise is often found with a matrix, a web-like pattern of the host rock that contains the stone. The matrix adds character to each piece, making every Turquoise gem unique.
Zircon: An Ancient and Diverse Gem
Zircon is a zirconium silicate mineral, which occurs in a wide range of colors due to impurities and radiation exposure. The most popular variety, blue Zircon, is created through heat treatment, which enhances its color.
Zircon is typically found in granitic rocks and metamorphic deposits. It is known for its high refractive index and dispersion, giving it a sparkling, diamond-like quality.
Major sources of Zircon include:
- India and Sri Lanka: Known for producing high-quality Zircon in various colors.
- Myanmar (Burma): Produces some of the finest blue Zircon.
- Australia and Brazil: Known for producing Zircon in a wide range of colors.
- Madagascar and Thailand: Also significant producers.
Zircon is a very durable gemstone, with a Mohs hardness of 6.5 to 7.5, making it suitable for everyday wear. It is also one of the oldest minerals on Earth, with some Zircon crystals dating back over 4 billion years.
Gemological Properties
| Gemstone | Color | Chemical Formula | Mohs Hardness | Origin | Refractive Index | Transparency | Luster | Specific Gravity |
|---|---|---|---|---|---|---|---|---|
| Tanzanite | Blue to violet | Ca₂Al₃(SiO₄)₃(OH) | 6 – 6.5 | Tanzania | 1.69 – 1.70 | Transparent to translucent | Vitreous | 3.1 – 3.4 |
| Turquoise | Blue to green | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 – 6 | Iran, U.S., China | 1.61 – 1.65 | Opaque | Waxy to greasy | 2.6 – 2.8 |
| Zircon | Colorless to blue | ZrSiO₄ | 6.5 – 7.5 | India, Sri Lanka, Myanmar | 1.92 – 2.01 | Transparent to translucent | Vitreous | 4.6 – 4.7 |
Tanzanite
- Color: Tanzanite is known for its violet-blue color, which is caused by the presence of trivalent iron (Fe³⁺) and is activated by irradiation.
- Hardness: 6–6.5 on the Mohs scale, which means it is relatively soft and requires careful handling.
- Luster: Vitreous (glassy).
- Transparency: Transparent to translucent.
- Cleavage: Perfect in one direction, which makes it sensitive to impact.
Turquoise
- Color: Ranges from pale blue to green, depending on the iron and copper content.
- Hardness: 5–6 on the Mohs scale, making it softer than most gemstones and prone to scratching.
- Luster: Waxy to greasy.
- Transparency: Opaque.
- Cleavage: None, but it is brittle and sensitive to heat and chemicals.
Zircon
- Color: Available in a wide range of colors, with blue Zircon being the most popular.
- Hardness: 6.5–7.5 on the Mohs scale, making it durable and suitable for everyday wear.
- Luster: Vitreous (glassy).
- Transparency: Transparent to translucent.
- Cleavage: Indistinct, but it can have inclusions that affect clarity.
Symbolism and Metaphysical Beliefs
Tanzanite
Tanzanite is believed to promote inner peace, emotional healing, and spiritual transformation. It is often associated with the third eye and crown chakras, making it a popular stone for meditation and self-reflection.
- Emotional Healing: Tanzanite is said to help release emotional blockages and trauma, allowing for emotional growth and balance.
- Spiritual Awareness: It is believed to enhance intuition, psychic abilities, and spiritual awakening.
- Protection: Some metaphysical practitioners believe that Tanzanite provides protection against negative energies.
Turquoise
Turquoise has long been considered a stone of protection and good fortune. It was especially revered by Native American tribes, who used it in ceremonies, as a symbol of spiritual connection and healing.
- Healing Properties: Turquoise is believed to support the respiratory and immune systems, and to aid in the treatment of asthma, allergies, and skin conditions.
- Emotional Stability: It is said to bring emotional balance and calmness, helping to reduce anxiety and stress.
- Protection: Turquoise is considered a guardian stone, protecting the wearer from harm and negative influences.
Zircon
Zircon is associated with wisdom, clarity, and divine energy. It is often used in spiritual practices to enhance mental clarity and insight.
- Wisdom and Clarity: Zircon is believed to improve mental clarity, decision-making, and focus.
- Spiritual Energy: It is associated with the third eye and crown chakras, enhancing intuition and spiritual connection.
- Love and Passion: Zircon is also considered a stone of love and passion, encouraging deep emotional connections and emotional stability.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of your birthstone jewelry. Here are some guidelines for each of the three December 21st birthstones:
Tanzanite
- Avoid heat and ultrasonic cleaners, as these can cause fading or damage.
- Use a soft cloth and mild soap and water to clean Tanzanite.
- Store separately to avoid scratching or chipping due to its perfect cleavage.
- Avoid exposure to harsh chemicals, as they can damage the stone.
Turquoise
- Turquoise is sensitive to heat and chemicals, so it should never be cleaned with steam or ultrasonic cleaners.
- Use a soft cloth and mild soap and water to clean Turquoise.
- Avoid prolonged exposure to sunlight, as it can fade the color.
- Store Turquoise away from hard surfaces, as it is brittle and prone to chipping.
Zircon
- Zircon is relatively hard and can be cleaned with steam or ultrasonic cleaners.
- Avoid heat, as some Zircons may change color when heated.
- Use a soft cloth and mild soap and water for regular cleaning.
- Store Zircon separately from softer gemstones to avoid scratching.
Conclusion
December 21st is a unique and significant birthstone date, associated with Tanzanite, Turquoise, and Zircon—three gems with distinct geological origins, rich histories, and deep cultural and metaphysical significance. From the rare and modern Tanzanite of Tanzania to the ancient and timeless Turquoise and Zircon, these stones offer a fascinating blend of beauty, symbolism, and utility.
Whether you are a gemstone enthusiast, a jewelry buyer, or simply curious about the meaning behind your birthstone, these December 21st gems provide a window into the world of mineralogy, history, and human belief systems. Their continued popularity in jewelry and spiritual practices is a testament to their enduring appeal and significance.