For those born on December 17th, the celebration of one’s birthday is marked not only by the turning of the calendar but also by the rich symbolism and beauty of three distinct gemstones: Tanzanite, Turquoise, and Zircon. These stones are more than decorative; they are treasured for their unique colors, geological properties, and the metaphysical qualities attributed to them across cultures and centuries. This article explores the significance of these December 17th birthstones, tracing their histories, their origins in nature, their gemological characteristics, and their roles in both ancient traditions and modern jewelry.
History and Lore
The concept of birthstones—assigning specific gemstones to each month—has roots that stretch back to biblical times and has evolved over centuries through cultural, religious, and commercial influences. December, the final month of the year, is unique in that it is one of only two months with three official birthstones: Tanzanite, Turquoise, and Zircon. These three gemstones were added to the birthstone list in the 20th and 21st centuries, reflecting a shift toward including more accessible and diverse gem materials in the tradition.
Tanzanite, the youngest of the three, was discovered in 1967 in Tanzania and was officially designated a birthstone in 2002. Turquoise, on the other hand, has a much longer history. Known as the "Turk Stone" due to its early trade through Turkey, it has been revered by ancient cultures from the Egyptians to the Navajo, who used it in jewelry and sacred rituals. Zircon, particularly blue zircon, has also been valued for millennia, appearing in jewelry and spiritual practices across the Middle East, South Asia, and beyond.
The association of these gemstones with December 17th reflects the month’s themes of transformation and renewal—whether through the Winter Solstice, the anticipation of a new year, or the spiritual symbolism of the stones themselves.
Geological Formation and Sources
Tanzanite
Tanzanite is a relatively rare gemstone, found only in a small area of Tanzania—specifically in the Merelani Hills of the Simanjiro region. It is a variety of the mineral zoisite, which has the chemical formula Ca₂Al₃(SiO₄)(OH)₃·H₂O. Tanzanite is known for its striking violet-blue to deep blue coloration, a result of trace amounts of vanadium in the crystal structure. The gemstone was first mined in the late 1960s and gained international popularity quickly due to its rarity and vivid color.
Tanzanite forms in metamorphic rock, specifically in areas where heat and pressure have altered the mineral composition of the surrounding environment. The Merelani Hills, where it is found, are rich in other gemstones, including sapphire and ruby, but tanzanite remains the most iconic and valuable.
Turquoise
Turquoise is a phosphate mineral with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. It forms in arid regions where copper-rich minerals react with phosphoric acid under oxidizing conditions. The finest turquoise is often found in deposits in Iran, the United States (particularly in Arizona and Nevada), and more recently in China and Australia.
The color of turquoise ranges from pale blue to deep green, depending on the amount of copper and iron in the stone. Turquoise is often found with matrix—natural mineral inclusions that can create intricate patterns, adding to the stone’s beauty and value.
Zircon
Zircon is a zirconium silicate with the chemical formula ZrSiO₄. It is one of the oldest minerals on Earth, with some zircon crystals dating back over 4 billion years. Blue zircon, the most popular variety, is created through heat treatment, which enhances its color and clarity. The natural color of zircon is typically yellow, brown, or red, but when heated to high temperatures, it can transform into a brilliant blue or colorless hue.
Zircon is found in a variety of geological environments, including igneous, metamorphic, and sedimentary rocks. Significant deposits are located in Thailand, Cambodia, Brazil, and Australia. Blue zircon is especially popular in jewelry due to its brilliance and affordability compared to other blue gemstones like sapphire or tanzanite.
Gemological Properties
Tanzanite
| Property | Value |
|---|---|
| Color | Violet-blue to deep blue |
| Chemical Formula | Ca₂Al₃(SiO₄)(OH)₃·H₂O |
| Hardness (Mohs) | 6 – 7 |
| Refractive Index | 1.69 – 1.70 |
| Specific Gravity | 3.1 – 3.4 |
| Cleavage | Perfect in one direction |
| Luster | Vitreous |
| Transparency | Transparent to translucent |
| Origin | Tanzania |
| Cut | Typically faceted in emerald or cushion cuts |
Tanzanite’s relatively low hardness and perfect cleavage make it susceptible to damage if not handled carefully. It is best suited for jewelry that is worn occasionally rather than daily wear.
Turquoise
| Property | Value |
|---|---|
| Color | Blue to green |
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O |
| Hardness (Mohs) | 5 – 6 |
| Refractive Index | 1.61 – 1.65 |
| Specific Gravity | 2.6 – 2.8 |
| Cleavage | None |
| Luster | Waxy to greasy |
| Transparency | Translucent to opaque |
| Origin | Iran, United States, China, Australia |
| Cut | Cabochon or carved into inlay or mosaic patterns |
Turquoise is best known for its use in cabochon form, which enhances its chatoyance and allows for the natural patterns within the stone to shine. Its softness requires it to be set in protective settings to prevent scratches and chips.
Zircon
| Property | Value |
|---|---|
| Color | Blue, yellow, red, brown |
| Chemical Formula | ZrSiO₄ |
| Hardness (Mohs) | 6.5 – 7.5 |
| Refractive Index | 1.92 – 2.01 |
| Specific Gravity | 4.5 – 4.8 |
| Cleavage | None |
| Luster | Vitreous |
| Transparency | Transparent to translucent |
| Origin | Thailand, Cambodia, Brazil, Australia |
| Cut | Faceted (especially emerald, round, and princess cuts) |
Zircon is prized for its high refractive index and dispersion, which give it a brilliant, fire-like sparkle. Blue zircon, in particular, is often used as a budget-friendly alternative to sapphire in jewelry.
Symbolism and Metaphysical Beliefs
Tanzanite
Tanzanite is often associated with spiritual awakening, emotional healing, and transformation. It is believed to enhance intuition, promote self-awareness, and foster a deeper connection with the universe. In metaphysical practices, tanzanite is used to open the third eye and crown chakras, making it a popular stone for meditation and psychic development.
As the birthstone for December 17th, tanzanite is also thought to bring success, protection, and positive energy. It is believed to support the wearer in making wise decisions, overcoming fears, and maintaining a calm and balanced state of mind.
Turquoise
Turquoise has long been revered as a stone of protection, healing, and good fortune. In ancient Egypt, it was used in amulets to ward off evil spirits and to protect warriors in battle. The Navajo and other Native American tribes used turquoise in jewelry and ceremonial objects, believing it to be a bridge between the physical and spiritual worlds.
Modern metaphysical practices associate turquoise with emotional stability, communication, and throat chakra activation. It is considered a calming stone that helps reduce anxiety, promote honesty, and enhance one’s ability to express themselves clearly.
Zircon
Zircon is known for its energy-boosting and clarity-enhancing properties. It is believed to stimulate the mind, improve concentration, and encourage a positive outlook. Blue zircon, in particular, is associated with love, peace, and emotional healing.
In some traditions, zircon is also linked to divine wisdom and spiritual growth. It is thought to help the wearer overcome past traumas and move forward with confidence and clarity.
Care and Cleaning
Proper care is essential to preserving the beauty and longevity of these December birthstones. Due to their varying hardness and sensitivity to heat and chemicals, each stone requires specific handling and cleaning methods.
Tanzanite
- Avoid heat and sunlight, as prolonged exposure can cause the color to fade.
- Clean with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners and steamers, which can damage the stone.
- Store separately from harder gemstones to prevent scratches.
Turquoise
- Avoid contact with water, acids, and chemicals, as these can cause the stone to lose color and become brittle.
- Clean with a soft cloth and a small amount of water or a mild jewelry cleaner.
- Avoid wearing it during physical activity or when exposed to harsh environments.
Zircon
- Zircon is relatively durable and can be cleaned with warm, soapy water and a soft brush.
- Avoid using ultrasonic cleaners for zircon, as it can cause internal fractures.
- Store zircon in a dry place to prevent any potential damage from moisture.
Conclusion
The birthstones of December 17th—Tanzanite, Turquoise, and Zircon—each carry a unique combination of beauty, history, and symbolism. From the rare and vibrant tanzanite of Tanzania to the ancient and enduring turquoise and the brilliant zircon, these gemstones reflect the rich tapestry of December’s traditions and the enduring power of gemstones in human culture.
Whether worn as a personal talisman, a meaningful gift, or simply as a stunning piece of jewelry, these birthstones serve as a reminder of the deep connections between nature, history, and human emotion. For those born on December 17th, they are not just stones—they are a legacy of protection, success, and spiritual growth.