For those born in December, the selection of birthstones offers a rare and intriguing opportunity: three distinct gemstones—turquoise, tanzanite, and zircon—each with its own unique allure, history, and symbolism. This article explores the geological, historical, and cultural significance of these three December birthstones, drawing exclusively from the data provided in the referenced sources. It delves into their origins, properties, and the meanings attributed to them across time and geography, offering a comprehensive view for gemstone enthusiasts, collectors, and those seeking a meaningful December birthstone.
A Unique Triad of December Birthstones
December is the only month with three officially recognized birthstones—turquoise, tanzanite, and zircon—each representing a different era and tradition. This triad of stones reflects the rich and varied history of gemstones in human culture, from ancient times to the modern era. The inclusion of multiple birthstones for a single month allows for a broader range of aesthetic and symbolic choices, accommodating different styles, budgets, and personal preferences.
While all three stones share a common color theme—blue—they differ significantly in their geological formation, physical properties, and cultural meanings. This diversity makes December’s birthstones particularly interesting from both a scientific and a cultural perspective.
History and Lore
Turquoise: The Ancient Gem of Power and Protection
Turquoise has one of the most ancient and well-documented histories among the December birthstones. As early as 3000 BCE, it was prized by the ancient Egyptians, who used it in jewelry and ceremonial objects. Pharaohs and other high-ranking officials adorned themselves with turquoise, believing it to be a source of protection and divine favor. The gem was also highly valued in ancient China, where artisans carved it into intricate pieces over 3,000 years ago.
Beyond its use in jewelry, turquoise was thought to possess powerful metaphysical properties. In medieval times, it was believed to protect the wearer from falling, especially when riding horses. Some sources indicate that the stone would break into several pieces at the approach of disaster. In Hindu traditions, turquoise was associated with wealth and prosperity. Specifically, it was believed that seeing turquoise after the new moon would bring fantastic wealth.
Turquoise was also a highly valued material in pre-Columbian Mesoamerican civilizations, particularly among the Aztecs and the Maya. It was used in ritual objects, ceremonial ornaments, and as a symbol of status and power.
Tanzanite: The Modern Marvel from Tanzania
Tanzanite is the youngest of the three December birthstones, having been discovered relatively recently in 1967. It was officially added to the birthstone list by the American Gem Trade Association (AGTA) in 2002. The gem is a variety of the mineral zoisite, and its striking blue and violet hues are due to the presence of vanadium.
Tanzanite is unique in that it is only found in one location on Earth: the Merelani Hills in northern Tanzania, near the base of Mount Kilimanjaro. This exclusivity adds to its value and allure. The gem formed under intense geological conditions—585 million years ago—during a period of extreme tectonic activity. In its natural state, tanzanite is brownish or yellowish green, and it is typically heat-treated to bring out the vibrant blue and violet tones that characterize it.
Tanzanite’s short but impactful history includes its commercial introduction by the jewelry brand Tiffany & Co., which launched it into the global market with a successful marketing campaign. Its rarity and beauty have made it a popular choice for modern jewelry, and its inclusion as a December birthstone has further increased its desirability.
Zircon: The Timeless Sparkler
Zircon is the oldest of the three December birthstones, with a history stretching back over 4.4 billion years. It is a naturally occurring mineral known as zirconium silicate, and it is highly prized for its brilliance and refractive index. Zircon is often mistaken for cubic zirconia, a synthetic gemstone, but it is a natural and distinct mineral with a different chemical composition and formation process.
Zircon has been used in jewelry for centuries, particularly in its colorless or blue forms. The gem is known for its high refractive index, which gives it a fire and sparkle comparable to that of a diamond. In fact, colorless zircon is sometimes used as a diamond simulant. Zircon is also notable for its high density, about 50% more than that of diamond.
Zircon is found in a variety of colors, including red, brown, yellow, green, and colorless, with blue being the most popular. The blue zircon is typically created through heat treatment, which enhances its color and brilliance. Zircon is also found in the same geological regions as sapphire, including countries like Sri Lanka, Myanmar, Vietnam, and Cambodia.
Geological Formation and Sources
Turquoise: A Product of Copper and Water
Turquoise is a phosphate mineral composed of copper and aluminum. It forms in arid environments where water percolates through copper-rich rock, particularly copper porphyry. This water becomes acidic due to the interaction with copper sulfides and then reacts with aluminum and potassium in the surrounding rock, precipitating turquoise into cavities.
This process results in the formation of turquoise in weathered volcanic rock and sedimentary rock in arid regions. The presence of veins or matrix patterns—remnants of the rock in which it formed—can affect the appearance of the stone. Turquoise is relatively soft, with a Mohs hardness of 5 to 6, making it susceptible to scratches and damage. It is also porous and can be easily discolored by oils, pigments, or changes in moisture content.
Tanzanite: A Unique Formation Under Tectonic Pressure
Tanzanite is a trigonal mineral and a variety of zoisite, with the chemical formula Ca₂Al₃(AlSiO₇)(SiO₄)O(OH)₃. Its striking blue and violet colors are due to the presence of vanadium, a trace element that becomes activated under specific geological conditions. Tanzanite is only found in the Merelani Hills of Tanzania, and it formed under extreme heat and pressure during tectonic activity that occurred 585 million years ago.
In its natural state, tanzanite appears brownish or greenish, but it is typically heat-treated to produce the vivid blue and violet hues that make it so desirable. This treatment is stable and does not alter the gemstone’s durability. Tanzanite is also pleochroic, meaning it displays different colors when viewed from different angles. This property is particularly noticeable under different lighting conditions—bluish under fluorescent light and violet under incandescent light.
Tanzanite’s limited source and the finite nature of the deposits have led to concerns about its future availability. Some estimates suggest that the known deposits may be depleted within a few decades, which could affect its market value.
Zircon: A Durable and Radiant Gem
Zircon is a zirconium silicate with the chemical formula ZrSiO₄. It forms in a variety of geological settings, including igneous, sedimentary, and metamorphic rocks. Zircon is known for its high refractive index, which contributes to its brilliance and fire, and it is also noted for its high density, approximately 50% greater than that of diamond.
Zircon is found in a wide range of colors, including red, brown, yellow, green, and colorless. The most popular variety is blue zircon, which is typically produced through heat treatment. This treatment enhances the gem’s color and clarity, making it a popular choice for jewelry.
Zircon is also notable for its high hardness, ranging from 6 to 7.5 on the Mohs scale, making it more durable than turquoise but less than tanzanite. It is generally stable under normal conditions, though some heat-treated zircons may revert to their original colors if exposed to intense light for prolonged periods.
Zircon is found in the same regions as sapphire, including Sri Lanka, Myanmar, Vietnam, and Cambodia. It is also found in Australia, Sri Lanka, and Madagascar.
Gemological Properties
| Property | Turquoise | Tanzanite | Zircon |
|---|---|---|---|
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O | Ca₂Al₃(AlSiO₇)(SiO₄)O(OH)₃ | ZrSiO₄ |
| Color | Blue to green, often with matrix patterns | Blue to violet | Red, brown, yellow, green, colorless (most popular is blue) |
| Hardness (Mohs) | 5–6 | 6–7 | 6–7.5 |
| Refractive Index | 1.60–1.63 | 1.69–1.70 | 1.92–2.01 |
| Luster | Waxy to vitreous | Vitreous | Vitreous |
| Transparency | Opaque to translucent | Transparent to translucent | Transparent to translucent |
| Specific Gravity | 2.6–2.8 | 3.3–3.4 | 4.6–4.8 |
| Treatment | Often stabilized with resins | Heat-treated to enhance color | Heat-treated to enhance blue color |
| Durability | Low; susceptible to scratches and chemical damage | Moderate; heat and light stable but susceptible to acid | High; generally durable |
Symbolism and Metaphysical Beliefs
Turquoise: The Stone of Protection and Prosperity
Turquoise has long been associated with protection, health, and good fortune. In ancient Egypt, it was believed to offer divine protection to the wearer. Medieval Europeans believed it could prevent falls, especially from horses, and that it would break apart before a disaster occurred. Hindu mystics believed that seeing turquoise after the new moon ensured wealth and prosperity.
In modern times, turquoise is still valued for its protective properties and is often used in spiritual practices and jewelry for those seeking inner peace and emotional stability. It is also associated with honesty, truth, and clear communication, making it a popular choice for those in need of emotional clarity.
Tanzanite: The Stone of Transformation and Healing
Tanzanite is relatively new in the realm of metaphysical gemstones, but it has quickly gained popularity for its healing and transformative properties. It is believed to promote emotional healing, self-awareness, and spiritual growth. Tanzanite is associated with the thulat (heart) and crown chakras, and it is used in chakra balancing and meditation.
Its pleochroic nature, where it displays different colors depending on the viewing angle, is seen as a symbol of adaptability and change. Tanzanite is also believed to aid in decision-making, clarity of thought, and emotional release. It is particularly useful for those going through personal or emotional transitions.
Zircon: The Stone of Clarity and Abundance
Zircon is associated with clarity, wisdom, and spiritual insight. In ancient times, it was believed to protect the wearer from poison and negative energy. Zircon is also known as the "gem of the night" because of its brilliance and fire, which make it shine even in low light.
Blue zircon, in particular, is believed to enhance focus, creativity, and intuition. It is often used in spiritual practices, especially for dream work and visioning. Zircon is also associated with abundance, success, and good fortune, making it a popular choice for those seeking to manifest their goals.
Care and Cleaning
Turquoise
Turquoise is a soft and porous gemstone, making it sensitive to chemicals, heat, and physical abrasion. To preserve its color and structure, it should be stored in a cool, dry place, away from direct sunlight. It should also be kept away from oils, lotions, and perfumes, as these can cause discoloration and degradation.
Cleaning turquoise should be done with care. A soft brush and mild soap in warm water is the safest method. Ultrasonic and steam cleaners are not recommended, as they can cause damage to the stone.
Tanzanite
Tanzanite is relatively stable under normal conditions, but it is susceptible to high temperatures and sudden temperature changes. It can also be damaged by acids, such as hydrochloric and hydrofluoric acid. For this reason, it is best to avoid wearing tanzanite in harsh environments.
Cleaning tanzanite should be done with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are not recommended, as they can cause structural damage to the gemstone.
Zircon
Zircon is more durable than turquoise, with a hardness of 6 to 7.5 on the Mohs scale, but it can still be damaged by rough handling or exposure to abrasive materials. It is generally stable under normal conditions, but some heat-treated zircons may revert to their original colors after prolonged exposure to bright light.
Cleaning zircon is best done with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are not recommended, as they can cause damage to the stone.
Conclusion
December’s birthstones—turquoise, tanzanite, and zircon—each offer a unique combination of beauty, history, and symbolism. Turquoise, with its ancient roots and protective properties, is a timeless gemstone with a deep cultural significance. Tanzanite, a modern marvel from Tanzania, brings a rare and captivating blue-violet hue to the December birthstone lineup. Zircon, with its high refractive index and brilliance, is a versatile and radiant gemstone that holds its own among the precious stones.
These three stones not only reflect the diverse history of gemstones but also provide a wide range of aesthetic and symbolic choices for December birthdays. Whether you prefer the soft, earthy tones of turquoise, the vibrant blues of tanzanite, or the sparkling brilliance of zircon, there is a December birthstone to suit every taste and occasion.
Choosing a December birthstone is not just about selecting a gemstone—it is about connecting with a piece of history, a symbol of meaning, and a beautiful expression of personal style.