For individuals born in the final month of the year, the birthstone selection is not a singular choice but a vibrant trio of gems, each distinguished by a unique shade of blue that reflects the cool elegance of winter. Those born in December are fortunate to count turquoise, tanzanite, and zircon as their official birthstones. While these gems share a predominant blue palette, they diverge significantly in their geological origins, gemological properties, historical narratives, and cultural symbolism. This comprehensive guide explores the distinct characteristics of these three remarkable stones, offering an in-depth look at why they are treasured by collectors, jewelers, and historians alike.
The concept of a singular birthstone for each month has evolved over centuries, but the modern consensus for December offers a rich diversity. From the ancient, opaque turquoise cherished by pharaohs and Native Americans to the relatively recent discovery of the violet-blue tanzanite, and the brilliant, multi-colored zircon, these gems provide a spectrum of options. This article will delve into the history, formation, scientific properties, and care instructions for each of December's birthstones, providing a definitive resource for gemstone enthusiasts and prospective buyers.
Turquoise: The Ancient Stone of Protection
Turquoise stands as the most traditional and historically significant of the December birthstones. It is a semi-translucent to opaque gem, prized for its distinctive color that ranges from sky blue to greenish blue. A defining characteristic of many turquoise specimens is the presence of "matrix"—veins of the host rock (often iron pyrite or sandstone) that remain embedded within the stone, creating intricate, web-like patterns.
History and Lore
Turquoise is one of the oldest known gemstones, with a history of human adornment and reverence stretching back thousands of years. Its name is derived from the French phrase pierre tourques, or "Turkish stone," reflecting its introduction to Europe from Persian mines via the Ottoman Empire. Ancient Egyptian artisans carved turquoise into amulets and jewelry, adorning the burial masks of pharaohs such as Tutankhamun. Similarly, in ancient China, the gem was carved into decorative objects more than 3,000 years ago.
The cultural significance of turquoise extends across numerous civilizations. The stone was believed to possess potent protective powers. From the 13th century, it was widely held that turquoise could safeguard the wearer from falls, particularly from horses, and that it would shatter upon the approach of danger or misfortune. Hindu mystics believed that gazing upon a turquoise after seeing the new moon would ensure great wealth. Among Native American tribes, particularly the Apache, the stone was deeply connected to the natural world; they believed turquoise could be found by following a rainbow to its end and that it imbued the wearer with skill and accuracy in archery. The Pueblo tribes considered it a living entity that would change color to warn of impending danger.
Geological Formation and Sources
Turquoise is a hydrous phosphate of copper and aluminum that forms in arid regions where acidic, copper-rich waters seep through aluminum-bearing rocks and evaporate. This process creates veins and nodules of the turquoise mineral within the host rock.
Historically, the most prized turquoise came from Persian mines in modern-day Iran. Persian turquoise is celebrated for its vivid, evenly saturated sky-blue color and its characteristically minimal to nonexistent matrix. The "Sleeping Beauty" variety, named for the mountain range in Arizona from which it was mined (prior to its closure), is renowned for its pure, robin's-egg blue color and smooth, uniform appearance. Other significant sources include the southwestern United States (Arizona, New Mexico, and Nevada), Chile, and Egypt.
Gemological Properties
Turquoise is valued for its unique color and matrix patterns rather than brilliance. It is an opaque gem with a waxy to dull luster when cut and polished. Its hardness on the Mohs scale typically ranges from 5 to 6, making it a relatively soft gemstone that requires careful handling.
Care and Cleaning
Due to its porosity and moderate hardness, turquoise is susceptible to damage from chemicals, heat, and sudden temperature changes. It can absorb oils and cosmetics, which may alter its color over time. Cleaning should be done gently with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. To prevent scratching, store turquoise jewelry separately from harder gems.
Tanzanite: The Modern Marvel of Merelani
Tanzanite is the newest addition to the birthstone calendar, having been discovered in the 20th century. It is a variety of the mineral zoisite and is celebrated for its striking violet-blue to ultramarine color. Its rarity is a key component of its allure; it is found in only one location on Earth: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro.
History and Discovery
Unlike ancient stones, tanzanite’s history is brief but dramatic. The gem was first identified in 1967 by a prospector named Manuel d’Souza. Initially, the stones were thought to be sapphires, but they were soon identified as a new variety of zoisite. Tiffany & Co. recognized the gem's potential and introduced it to the world in 1968, naming it after the country of its origin. The marketing campaign hailed it as "the most beautiful blue gemstone to be discovered in 2,000 years," and it was quickly adopted as a modern birthstone for December.
Geological Formation and Sources
Tanzanite formed approximately 585 million years ago during a massive metamorphic event. The intense heat and pressure of the earth's crust transformed the host rock, allowing for the crystallization of zoisite. The specific geological conditions required for its formation are so unique that geologists estimate the area where tanzanite is found is a mere 4 square kilometers, making it thousands of times rarer than diamond.
The sole source is the Merelani Hills of Tanzania. Mining is often small-scale and challenging, contributing to the stone's limited supply and high value.
Gemological Properties
Tanzanite is renowned for its remarkable trichroism, a property where the stone displays three different colors when viewed from three different crystallographic directions: blue, purple, and burgundy. The most desirable color is a deep, vibrant blue with a distinct violet undertone. To enhance this color, most tanzanite is heat-treated, a process that is considered permanent and standard in the industry.
- Chemical Composition: Ca2Al3(SiO4)3(OH)
- Hardness: 6.5 to 7 on the Mohs scale
- Refractive Index: 1.691 – 1.700
Care and Cleaning
With a hardness of 6.5 to 7, tanzanite is durable enough for most jewelry but is softer than sapphire or diamond. It has perfect cleavage in one direction, meaning it can split if struck with sufficient force along that plane. Therefore, it should be protected from hard knocks. Cleaning is safe with warm, soapy water and a soft brush. Avoid sudden temperature changes and ultrasonic cleaners, which can cause damage due to its cleavage.
Zircon: The Multifaceted Gem of Clarity
Zircon is one of the oldest minerals on Earth, yet it remains a lesser-known gem to the general public. It should not be confused with cubic zirconia, a synthetic diamond simulant. Natural zircon is a brilliant and fiery gemstone available in a wide spectrum of colors, though the blue variety is most commonly associated with December.
History and Lore
Zircon has been used in jewelry for centuries. In the Middle Ages, it was believed to promote honor, riches, and wisdom in its wearer. It was also thought to induce sleep and ward off evil spirits. The name "zircon" may be derived from the Persian zargun, meaning "gold-colored," though it is rarely yellow today. The gem’s high refractive index gives it exceptional brilliance, often leading it to be mistaken for diamond in historical jewelry.
Geological Formation and Sources
Zircon is a zirconium silicate that forms in igneous and metamorphic rocks. It is a heavy, durable mineral that is highly resistant to weathering. As an accessory mineral, it is found in many rock types and is often found as detrital grains in sedimentary deposits.
Major sources for gem-quality zircon include Thailand, Sri Lanka, and Vietnam. Australia is also a significant source, particularly for the brownish-red zircon that is often heat-treated to achieve a blue color.
Gemological Properties
Zircon is one of the heaviest gemstones, a characteristic that gives it a feeling of substance when set in jewelry. It possesses a very high refractive index (1.92-2.01) and strong dispersion, which gives it a fire that rivals that of diamond.
- Color: Colorless, blue, green, yellow, brown, and orange. Blue is the most popular for December.
- Hardness: 6.5 to 7.5 on the Mohs scale
- Crystal System: Tetragonal
- Treatments: Much of the blue zircon on the market is heat-treated from brownish zircon. This treatment is stable and widely accepted.
Care and Cleaning
Zircon is relatively hard but has poor toughness due to its fragility. It is brittle and can be easily chipped or abraded if knocked against a hard surface. It is sensitive to sudden temperature changes, which can cause internal fractures. Cleaning should be done with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners. It is best suited for earrings or pendants, which are less likely to receive impacts than rings.
A Comparative Overview of December's Birthstones
To provide a clear comparison of the primary gemological properties of the three main December birthstones, the following table is provided based on information derived from the sources.
| Gemstone | Hardness (Mohs Scale) | Chemical Composition | Key Visual Characteristic | Primary Source Locations |
|---|---|---|---|---|
| Turquoise | 5 - 6 | Hydrous phosphate of copper & aluminum | Opaque, sky-blue to green color with matrix | Iran, USA (Arizona, Nevada), Chile, Egypt |
| Tanzanite | 6.5 - 7 | Ca2Al3(SiO4)3(OH) | Trichroism (blue, purple, burgundy) | Tanzania (Merelani Hills) |
| Zircon | 6.5 - 7.5 | ZrSiO4 | High brilliance and fire (dispersion) | Thailand, Sri Lanka, Vietnam, Australia |
Symbolism and Metaphysical Beliefs
The symbolism attached to each of December's birthstones is as varied as the gems themselves. While all three are associated with positive attributes, their specific meanings resonate with different personal aspirations.
- Turquoise is overwhelmingly associated with protection, healing, and tranquility. It is considered a grounding stone that connects the wearer to the natural world and spiritual stability. Its lore is rooted in safeguarding the physical body and ensuring good fortune.
- Tanzanite, as a modern discovery, is linked to transformation, intuition, and spiritual growth. It is believed to open the mind to new possibilities and enhance psychic abilities and spiritual awareness. Its vibrant color is thought to stimulate the throat and crown chakras, promoting clear communication and a higher consciousness.
- Zircon is associated with clarity of thought, honor, and wisdom. It is believed to help its wearer achieve a balanced state of mind, ward off negative energy, and attract prosperity. Its brilliant fire is seen as a metaphor for enlightenment and spiritual purity.
Caring for Your December Birthstone Jewelry
Proper care is essential to maintain the beauty and longevity of any gemstone. Given the distinct properties of turquoise, tanzanite, and zircon, a tailored approach to their maintenance is required.
General Care Principles: * Avoid Harsh Chemicals: All three gems should be protected from household cleaners, cosmetics, and perfumes. Apply these products before putting on your jewelry. * Separate Storage: Store each piece of jewelry separately in a soft-lined box or pouch to prevent scratching. Zircon, in particular, can be scratched by other gems and can scratch softer stones like turquoise. * Remove During Activity: Take off jewelry before engaging in sports, heavy housework, or gardening to protect it from impact and abrasion.
Specific Cleaning Instructions: * Turquoise: Use warm, soapy water and a soft brush. Dry thoroughly with a soft cloth. Avoid soaking and never use ultrasonic or steam cleaners. * Tanzanite: Clean with warm, soapy water and a soft brush. Rinse well. While generally safe in warm water, avoid extreme temperature changes and ultrasonic cleaners due to its cleavage. * Zircon: Clean with warm, soapy water and a soft brush. Be gentle due to its brittleness. Avoid ultrasonic cleaners and steam cleaners. Do not expose zircon to sudden temperature changes.
Conclusion
The birthstones for December—turquoise, tanzanite, and zircon—offer a remarkable range of choices that cater to every taste and style. They collectively represent a spectrum of blue, from the earthy, robin's-egg hues of ancient turquoise to the deep, violet-blue of tanzanite and the brilliant, multi-hued fire of zircon. Each stone tells a unique story: turquoise speaks of ancient history, protection, and connection to the earth; tanzanite embodies modern discovery, rarity, and spiritual evolution; and zircon represents timeless wisdom, clarity, and brilliance. For the December-born individual, these gems are more than mere adornments; they are symbols of personal identity, carrying with them centuries of lore, scientific wonder, and enduring beauty. Whether chosen for their historical significance, metaphysical properties, or simply their captivating color, these three gemstones ensure that December's legacy is one of vibrant and diverse splendor.