The final month of the year is associated with a distinct trio of gemstones, all sharing a cool blue palette that evokes the winter landscape. For individuals born on December 26th, the primary birthstone is Tanzanite, a gemstone celebrated for its mesmerizing violet-blue hues and remarkable rarity. While Turquoise and Zircon are also recognized birthstones for December, Tanzanite stands out as the most valuable and a relatively modern addition to the birthstone calendar, having been discovered in the mid-20th century.
This article explores the distinct characteristics of Tanzanite, tracing its geological origins in a single remote location, examining its unique gemological properties, and uncovering the symbolic meanings attached to this extraordinary stone.
History and Lore
Unlike ancient gemstones such as Turquoise, which has been prized for millennia, Tanzanite has a very specific and recent history. It was discovered in 1967 in Tanzania, the country from which it derives its name. Geologically, it is a variety of the mineral zoisite. Its journey from discovery to global prominence was swift, largely due to the efforts of the jewelry company Tiffany & Co., which recognized its potential and introduced it to the market in 1968, promoting it as "the most beautiful blue gemstone discovered in 2,000 years."
The establishment of standardized birthstone lists has seen several updates over the years. The modern birthstone list for December was expanded to include Tanzanite in 2002, acknowledging its growing popularity and significance in the gem trade. This addition brought the total number of official December birthstones to three, alongside Turquoise and Zircon, offering a wider variety of choices for those born in the month.
Geological Formation and Sources
Tanzanite’s geological story is as unique as its color. It is formed from the mineral zoisite and is found in only one known location in the world: a small, four-square-kilometer mining area in the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. This extreme geographic limitation makes Tanzanite significantly rarer than diamonds, contributing to its high value and desirability.
The gemstone's formation is linked to a specific geological event. The intense heat of a natural forest fire, occurring roughly 585 million years ago, altered the chemical composition of the zoisite deposits, infusing them with the trace elements vanadium and chromium that are responsible for its signature blue and violet colors. The mining of Tanzanite is a localized operation, and the scarcity of the source material ensures that it remains a prized commodity in the global gem market.
Gemological Properties
Tanzanite is renowned not only for its color but also for a unique optical phenomenon that sets it apart from many other gemstones. It exhibits strong trichroism, a property that allows it to display three different colors when viewed from three different crystallographic directions. Depending on the angle, a piece of Tanzanite can appear a deep blue, a vibrant violet, or a reddish-burgundy. This dynamic quality gives the stone a captivating depth and complexity.
Most Tanzanite available on the market has been heat-treated to achieve its stable blue-to-violet hues. This heating process is a standard practice and is considered permanent.
The gemological properties of Tanzanite are as follows:
- Mineral: Zoisite
- Chemical Composition: Ca2Al3(SiO4)3(OH)
- Hardness (Mohs Scale): 6 to 7
- Crystal System: Orthorhombic
- Refractive Index: 1.691 – 1.700
- Specific Gravity: 3.35
- Luster: Vitreous (glass-like)
With a hardness of 6 to 7 on the Mohs scale, Tanzanite is moderately durable but is softer than Sapphire or Diamond. This makes it suitable for jewelry that is worn with care, such as earrings and pendants, but requires more attention in rings that are exposed to potential knocks and scratches.
Symbolism and Metaphysical Beliefs
Tanzanite is a stone rich in symbolism and is often associated with transformation and spiritual growth. Its rapid rise from an unknown mineral to a world-renowned gemstone is itself a metaphor for metamorphosis. Many believe that Tanzanite carries specific metaphysical properties that can benefit the wearer.
- Spiritual Enlightenment: It is widely thought to enhance spiritual awareness, opening the mind to new insights and fostering a deeper understanding of oneself and the universe.
- Communication and Clarity: The stone is linked to the throat chakra and is believed to promote clear communication and facilitate honest, heartfelt expression.
- Calming Influence: In some beliefs, Tanzanite has a calming effect on the mind, helping to alleviate stress and anxiety, and promoting a sense of tranquility.
These attributes make it a popular choice not just for its aesthetic appeal but also for those seeking a gemstone with deeper meaning.
Care and Cleaning
Due to its moderate hardness and lack of cleavage, Tanzanite requires specific care to maintain its beauty. While it is not exceptionally fragile, it is more susceptible to scratching and chipping than harder gems like Sapphire.
- Cleaning: The safest method for cleaning Tanzanite is with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaners, as the heat and vibrations can potentially damage the stone, especially if it has been fracture-filled.
- Storage: To prevent scratches, store Tanzanite jewelry separately from other gemstones, ideally in a soft cloth or a lined jewelry box.
- Handling: It is advisable to remove Tanzanite jewelry before engaging in activities that could subject it to hard impacts, such as sports or heavy manual work.
Conclusion
Tanzanite is a truly exceptional gemstone, distinguished by its unique origin, captivating trichroic properties, and profound symbolism. As the primary birthstone for December 26th, it represents a perfect blend of modern rarity and timeless beauty. Its limited source near Mount Kilimanjaro ensures its status as one of the world's most sought-after gems, while its rich violet-blue color continues to enchant gemstone enthusiasts and jewelry buyers alike. Whether valued for its aesthetic appeal, its spiritual significance, or its geological uniqueness, Tanzanite remains a standout choice in the world of colored gemstones.