December is one of the few months with four official birthstones: Turquoise, Tanzanite, Blue Topaz, and Blue Zircon. Among these, Turquoise and Tanzanite stand out for their unique coloration, historical significance, and popularity in fine gold jewelry. This article explores the geological, cultural, and aesthetic properties of Turquoise and Tanzanite, focusing on their use in gold jewelry and their enduring appeal among collectors and jewelry enthusiasts.
History and Lore of Turquoise and Tanzanite
Both Turquoise and Tanzanite carry rich historical and cultural legacies that have shaped their perception as December birthstones.
Turquoise
Turquoise has been revered for thousands of years across multiple civilizations. Its use dates back to ancient Egypt, where it was often inlaid in jewelry and amulets. The Egyptians believed that Turquoise was sacred and associated it with the gods. Pharaohs wore Turquoise as a symbol of protection and divine favor. In Mesopotamia and the Indus Valley, Turquoise was similarly valued for its spiritual significance and aesthetic appeal.
In the Americas, Native American tribes such as the Navajo, Zuni, and Pueblo peoples have long used Turquoise in jewelry and ceremonial objects. They associate the stone with health, prosperity, and harmony with nature. Turquoise was often used in healing rituals and as a protective talisman. The stone’s connection to the sky and water also made it a symbol of wisdom and serenity.
In the modern era, Turquoise was officially recognized as a December birthstone in the 20th century, though it had long been associated with the month in various cultural traditions. Its calming blue-green hues and spiritual connotations continue to make it a popular choice for December jewelry, especially in gold settings that highlight its natural beauty.
Tanzanite
Tanzanite, by contrast, is a much younger gemstone in terms of discovery and commercial use. It was first identified in Tanzania in the 1960s by a local Maasai herdsman who found unusual violet-blue crystals near Mount Kilimanjaro. The stone was later named "Tanzanite" in honor of Tanzania, where it is the only known source in the world.
Tanzanite was officially designated as a December birthstone in the 1980s, reflecting its rapid rise in popularity due to its striking color and the limited availability of the stone. The gemstone's discovery and naming were strategically timed to create a sense of exclusivity and desirability, which contributed to its success in the jewelry market.
The gemstone is often associated with spiritual transformation and emotional healing. Its deep blue-violet hues are said to stimulate intuition and encourage personal growth. These metaphysical properties, combined with its rarity and beauty, have made Tanzanite a favored choice in gold jewelry for December-born individuals.
Geological Formation and Sources
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper. Its chemical formula is CuAl₆(PO₄)₄(OH)₈·4H₂O. The presence of copper gives Turquoise its characteristic blue color, while iron imparts a greenish hue. The degree of hydration also affects the color, with more water resulting in lighter tones.
Turquoise forms in the oxidation zones of copper deposits, typically in arid regions where weathering and mineralization processes are active. It is commonly found in association with other minerals such as quartz, calcite, and iron oxides. The presence of these minerals can create beautiful matrix patterns in Turquoise, adding to its visual appeal.
Major sources of Turquoise include:
United States: The Southwestern U.S., particularly Arizona and New Mexico, is one of the most famous sources of high-quality Turquoise. The Cerrillos Hills in New Mexico and the Bisbee and Morenci mines in Arizona are well-known for producing Turquoise with rich blue colors and attractive matrix patterns.
Nepal: Known for producing a unique, light-blue Turquoise with a fine grain and excellent transparency.
China: A major supplier of Turquoise, especially from the Yunnan and Gansu provinces. Chinese Turquoise often has a greener coloration due to higher iron content.
Iran: Historically, Iran has been a significant source of Turquoise, particularly for the Persian market. Iranian Turquoise is known for its deep blue color and fine grain.
Tanzanite
Tanzanite is a variety of the mineral zoisite. Its chemical formula is Ca₂Al₃(SiO₄)(Si₂O₇)O(OH) and it is distinguished from other zoisite varieties by its trichroic nature—meaning it can display three different colors (blue, violet, and brown) depending on the angle of light. Tanzanite is heat-treated to enhance its color, turning the original brownish zoisite into the deep blue-violet color that is highly desirable.
Tanzanite is found exclusively in the Merelani Hills of Tanzania, near Mount Kilimanjaro. The area's unique geological conditions—where tectonic activity and metamorphic processes have created the right environment for zoisite to form—make it the world's only source for this gemstone.
The Merelani mine is the primary source of Tanzanite. However, the mine is expected to be depleted in the coming decades, which could affect the availability of new Tanzanite in the future. This scarcity has only increased the stone’s value and desirability in the jewelry market.
Gemological Properties
Turquoise
Turquoise is a relatively soft gemstone with a hardness of 5 to 6 on the Mohs scale. This makes it more susceptible to scratches and damage compared to harder gemstones like diamonds or sapphires. It is also porous and sensitive to acids and other chemicals, so it requires careful handling and cleaning.
Key Properties of Turquoise:
- Hardness (Mohs): 5 to 6
- Color: Ranges from sky blue to greenish-blue, depending on the mineral content and hydration.
- Luster: Waxy to greasy
- Transparency: Usually opaque to translucent
- Refractive Index: 1.61 to 1.65
- Specific Gravity: 2.6 to 2.8
- Crystal System: Trigonal
- Common Cuts: Cabochon, which enhances the stone's color and prevents it from being scratched.
Turquoise is often stabilized with resins or oils to improve its durability and color consistency. The most common cut is the cabochon, which highlights the stone's natural color and patterns.
Tanzanite
Tanzanite is a much harder gemstone compared to Turquoise, with a hardness of 6 to 7 on the Mohs scale. It is more durable and suitable for everyday wear, making it a popular choice for rings, pendants, and earrings.
Key Properties of Tanzanite:
- Hardness (Mohs): 6 to 7
- Color: Deep blue-violet, with trichroism (displaying three different colors depending on the angle of light)
- Luster: Vitreous
- Transparency: Transparent to translucent
- Refractive Index: 1.69 to 1.70
- Specific Gravity: 3.35 to 3.40
- Crystal System: Monoclinic
- Common Cuts: Faceted cuts such as emerald, oval, and round, which showcase the stone's brilliance and color.
Tanzanite is typically heat-treated to enhance its color and is sometimes irradiated to improve its blue-violet hue. These treatments are stable and do not affect the stone’s durability or appearance.
Symbolism and Metaphysical Beliefs
Both Turquoise and Tanzanite are associated with a range of metaphysical and symbolic meanings, which have contributed to their popularity as birthstones.
Turquoise
Turquoise has long been associated with protection, wisdom, and tranquility. In many cultures, it is believed to promote emotional balance, enhance communication, and encourage personal growth. It is also considered a stone of abundance and good fortune, making it an ideal gift for December birthdays.
Some of the key metaphysical properties attributed to Turquoise include:
- Emotional Healing: Turquoise is believed to help release negative emotions and promote a sense of calm and inner peace.
- Communication: The stone is associated with clear and honest communication, making it a popular choice for those who wish to express themselves more effectively.
- Spiritual Growth: Turquoise is linked to the throat and third eye chakras, supporting spiritual insight and intuition.
These properties have made Turquoise a popular choice in gold jewelry, especially for those seeking a stone that supports emotional and spiritual well-being.
Tanzanite
Tanzanite is associated with transformation, intuition, and spiritual insight. It is believed to help individuals navigate change and embrace new perspectives. The gemstone is also associated with emotional healing and the ability to overcome past traumas.
Some of the key metaphysical properties attributed to Tanzanite include:
- Transformation: Tanzanite is a stone of transformation and change, helping individuals let go of the past and embrace new possibilities.
- Intuition: The stone is believed to enhance intuition and psychic abilities, making it a powerful tool for meditation and spiritual growth.
- Emotional Healing: Tanzanite is associated with the heart and throat chakras, promoting emotional healing and the ability to express feelings.
These properties make Tanzanite a powerful and meaningful gemstone, especially when set in gold, which enhances its beauty and symbolic significance.
Care and Cleaning of Turquoise and Tanzanite in Gold Jewelry
Given their different physical properties, Turquoise and Tanzanite require different care and cleaning methods to maintain their beauty and longevity.
Caring for Turquoise in Gold Jewelry
Turquoise is a relatively soft and porous gemstone, so it requires gentle handling and cleaning. It should not be exposed to harsh chemicals, heat, or sunlight for prolonged periods, as this can cause it to fade or become brittle.
Care Tips for Turquoise Jewelry:
- Avoid Exposure to Chemicals: Remove Turquoise jewelry before using household cleaners, perfumes, or lotions.
- Clean Gently: Use a soft, damp cloth to clean Turquoise. Avoid using ultrasonic cleaners or steamers, as these can damage the stone.
- Store Properly: Store Turquoise jewelry in a cool, dry place, preferably in a soft cloth or jewelry box to prevent scratches.
- Avoid Heat: Prolonged exposure to heat can cause Turquoise to lose moisture and become brittle.
Caring for Tanzanite in Gold Jewelry
Tanzanite is a harder and more durable gemstone than Turquoise, making it suitable for daily wear. However, it should still be handled with care to avoid scratches and damage.
Care Tips for Tanzanite Jewelry:
- Avoid Harsh Chemicals: Remove Tanzanite jewelry before using cleaning products or perfumes.
- Clean with Mild Soap: Use a mild soap and warm water to clean Tanzanite. Gently scrub the stone with a soft brush, then rinse and dry with a soft cloth.
- Avoid Steam Cleaners and Ultrasonic Cleaners: These can potentially damage the stone or its setting.
- Store in a Cool, Dry Place: Store Tanzanite jewelry in a jewelry box to prevent scratches and damage.
Conclusion
Turquoise and Tanzanite are two of the most captivating and meaningful December birthstones, each with a unique history, geological origin, and cultural significance. Turquoise, with its ancient roots and calming blue-green hues, continues to be a favorite among jewelry collectors and those who value its spiritual properties. Tanzanite, a more modern gemstone, has quickly become a symbol of transformation and intuition, making it a powerful and beautiful choice for December jewelry.
When set in gold, both stones shine with an elegant warmth that enhances their natural beauty. Whether you are choosing a Turquoise or Tanzanite gold necklace for yourself or as a gift, you are selecting a piece of jewelry that carries centuries of tradition, meaning, and artistry.