For those born on December 21st, the birthstone designation includes three distinct yet equally captivating gemstones: Tanzanite, Turquoise, and Blue Zircon. Each of these stones shares a common color theme—blue—while differing in origin, formation, and historical significance. This article explores the unique characteristics, cultural symbolism, and gemological properties of these December 21 birthstones, drawing from a detailed analysis of the sources available.
Introduction
The birthstone tradition is an ancient practice that links gemstones to the months of the year and, in many cultures, to zodiac signs. December is represented by three official birthstones—Turquoise, Tanzanite, and Blue Zircon—with the alternative being Blue Topaz. For those born on December 21st, these stones hold special significance. They are not only treasured for their beauty but also for the qualities they are believed to impart: success, protection, and prosperity.
This article will delve into the historical and cultural significance of these gems, their geological formation, and their symbolic meanings. It will also discuss how they are used in jewelry and the care they require, based on their physical properties.
History and Lore
Turquoise: The Ancient Blue
Turquoise has been revered for thousands of years. Its name derives from the French pierre turquoise, meaning “Turkish stone,” a reference to how it was brought to Europe via Turkish markets. In fact, Turquoise is one of the oldest known gemstones to be used in jewelry. It has been found in ancient Egyptian tombs and was highly valued by the Egyptians, who believed it to bring protection and good fortune.
In the Middle East and Central Asia, Turquoise was worn for protection and healing. In Native American cultures, particularly among the Navajo and Zuni, Turquoise is considered a sacred stone, symbolizing health, wisdom, and spiritual power. These traditions have continued into the modern era, where Turquoise remains a popular choice for December birthdays and is often associated with the zodiac sign Sagittarius.
Tanzanite: The Modern Marvel
Tanzanite is a much younger gemstone, first discovered in the 1960s in Tanzania, near Mount Kilimanjaro. It was initially marketed by Tiffany & Co., and its striking blue to violet-blue color quickly made it a sought-after gem. Unlike Turquoise, which has a history spanning millennia, Tanzanite is a relatively recent addition to the world of gemstones.
Tanzanite is a variety of the mineral zoisite, and its vivid blue color is typically enhanced through heat treatment. One of its most notable features is its strong pleochroism, meaning it displays different colors when viewed from different angles. Tanzanite’s rarity adds to its allure; it is only found in a small area in Tanzania, making it a unique and valuable gem.
Blue Zircon: A Sparkling Legacy
Blue Zircon has been used in jewelry for over 2,000 years. Zircon is a naturally occurring mineral that can be found in a wide range of colors, including red, yellow, brown, and colorless. The blue variety is particularly popular and is often produced through heat treatment. Blue Zircon is known for its high refractive index, which gives it a brilliance that is often compared to diamonds.
Zircon has also played a role in scientific discovery. Due to the presence of trace amounts of uranium and thorium, Zircon has been instrumental in the development of radiometric dating. Some of the oldest Zircon crystals found are over 4.4 billion years old, making them some of the oldest known minerals on Earth.
Geological Formation and Sources
Turquoise Formation and Origin
Turquoise is formed by the interaction of copper-rich groundwater with the surrounding bedrock. Over time, this process creates an opaque stone with a range of blue and green hues. The dark veins and patterns visible in Turquoise, known as matrix, are derived from the minerals in the surrounding rock.
The primary sources of Turquoise include the United States (especially Arizona and Nevada), Iran, China, and Egypt. The quality and color of Turquoise can vary significantly depending on the location of the mine and the mineral composition of the surrounding rock.
Tanzanite Formation and Origin
Tanzanite is a rare gemstone that is found exclusively in the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. It is a metamorphic mineral, formed under high pressure and temperature conditions. The blue color of Tanzanite is due to trace amounts of vanadium in its crystal structure.
Because of its limited geographic origin, Tanzanite is considered a highly valuable and collectible gemstone. Its unique color and rarity make it a popular choice for fine jewelry, particularly in the form of pendants, earrings, and rings.
Blue Zircon Formation and Origin
Zircon is a zirconium silicate mineral that is found in a variety of geological settings. Blue Zircon is created through heat treatment, which stabilizes the color and enhances its brilliance. Natural Zircon can be found in several countries, including Thailand, Cambodia, Vietnam, and Sri Lanka.
Zircon is known for its high refractive index and dispersion, giving it a brilliant, diamond-like appearance. It is often used as a diamond substitute, particularly in vintage and antique jewelry. The availability of large, high-quality Blue Zircons makes it a popular choice for jewelry, especially for those who prefer affordable yet elegant gemstones.
Gemological Properties
Turquoise
- Color: Ranges from blue to green, with a translucent to opaque appearance.
- Hardness: 5–6 on the Mohs scale.
- Luster: Waxy to dull.
- Clarity: Typically opaque, with visible matrix patterns.
- Chemical Formula: CuAl₆(PO₄)₄(OH)₈·4H₂O.
- Specific Gravity: 2.6–2.8.
- Refractive Index: 1.61–1.65.
Turquoise is relatively soft compared to other gemstones, making it susceptible to scratches and damage from heat and chemicals. It is also porous, which can make it sensitive to oils and solvents.
Tanzanite
- Color: Blue to violet-blue, with strong pleochroism.
- Hardness: 6–7 on the Mohs scale.
- Luster: Vitreous.
- Clarity: Usually transparent to slightly included.
- Chemical Formula: Ca₂Al₃(SiO₄)₃(OH)₃.
- Specific Gravity: 3.1–3.4.
- Refractive Index: 1.69–1.70.
Tanzanite is a relatively durable gemstone but should be handled with care, as it can be sensitive to heat and light. Heat treatment is commonly used to enhance its color, and exposure to extreme temperatures can cause color fading or changes.
Blue Zircon
- Color: Blue, sometimes with a slight green or violet hue.
- Hardness: 6–7.5 on the Mohs scale.
- Luster: Vitreous.
- Clarity: Often transparent with visible inclusions.
- Chemical Formula: ZrSiO₄.
- Specific Gravity: 4.5–4.7.
- Refractive Index: 1.92–2.01.
Blue Zircon is known for its high refractive index, which gives it a brilliant, fiery appearance. It is more durable than Turquoise but can still be damaged by sudden temperature changes or chemical exposure.
| Gemstone | Color | Hardness (Mohs) | Chemical Formula | Origin |
|---|---|---|---|---|
| Turquoise | Blue-Green | 5–6 | CuAl₆(PO₄)₄(OH)₈·4H₂O | Arizona, Iran, Egypt |
| Tanzanite | Blue-Violet | 6–7 | Ca₂Al₃(SiO₄)₃(OH)₃ | Tanzania |
| Blue Zircon | Blue | 6–7.5 | ZrSiO₄ | Thailand, Cambodia, Vietnam |
Symbolism and Metaphysical Beliefs
Turquoise: A Stone of Protection and Prosperity
Throughout history, Turquoise has been believed to possess protective and healing properties. In ancient Egypt, it was used in amulets and was thought to ward off evil and bring good fortune. In Native American traditions, it is associated with spiritual power and is often used in rituals for healing and divination.
Modern metaphysical beliefs also attribute Turquoise with the power to promote calmness, encourage honesty, and enhance communication. It is believed to help the wearer express their emotions more clearly and to attract positive energy.
Tanzanite: A Stone of Transformation and Intuition
Tanzanite is often associated with transformation and intuition. It is believed to enhance spiritual awareness and to help individuals connect with their higher selves. Many people use Tanzanite for meditation and as a tool for personal growth and emotional healing.
Tanzanite is also linked to the throat chakra, which is associated with communication and self-expression. It is thought to help individuals express their thoughts and feelings more effectively and to promote harmony and understanding in relationships.
Blue Zircon: A Stone of Clarity and Insight
Blue Zircon is believed to enhance mental clarity and to help individuals see situations more clearly. It is often used for problem-solving and decision-making, as it is thought to help the wearer see the bigger picture and to make more informed choices.
In metaphysical practices, Blue Zircon is also associated with protection and purification. It is believed to help cleanse the mind and body of negative energy and to promote a sense of inner peace and balance.
Care and Cleaning
Each of the December 21 birthstones requires specific care due to their unique properties.
Turquoise
Because Turquoise is relatively soft and porous, it should be handled with care. It is sensitive to oils, lotions, and household chemicals, which can cause it to lose its color or become damaged. It should be stored separately from harder gemstones to avoid scratches.
Turquoise should be cleaned with a soft cloth and mild soap. It should not be exposed to extreme heat or prolonged sunlight, as this can cause it to fade or become brittle.
Tanzanite
Tanzanite is more durable than Turquoise but can still be affected by heat and light. It should be stored in a cool, dark place to preserve its color and to prevent fading.
Tanzanite can be cleaned with a soft cloth and mild soap. It should not be exposed to harsh chemicals or ultrasonic cleaners, as these can cause damage to the stone or its setting.
Blue Zircon
Blue Zircon is relatively durable and can withstand normal wear and tear. However, it should still be handled with care, as it can be affected by sudden temperature changes and chemical exposure.
Blue Zircon can be cleaned with a soft cloth and mild soap. It can also be cleaned with ultrasonic cleaners, but care should be taken to avoid exposing it to harsh chemicals or abrasive materials.
Conclusion
The birthstones for December 21—Tanzanite, Turquoise, and Blue Zircon—each offer a unique combination of beauty, history, and symbolism. These gems are not only treasured for their aesthetic appeal but also for the qualities they are believed to bring to the wearer. Whether chosen for their protective properties, their vibrant colors, or their rarity, these gemstones continue to captivate gemstone enthusiasts, jewelry lovers, and those who believe in the power of gemstones.
Understanding the geological properties, historical significance, and cultural symbolism of these gems provides a deeper appreciation for their role in both the jewelry industry and the broader world of gemology. As the December 21 birthstone, they serve as a reminder of the enduring fascination with gemstones and their place in human history and culture.