For those born in the final month of the year, the selection of a birthstone is uniquely abundant. December is one of only two months that boasts three distinct gemstones officially recognized by the modern jewelry trade: Turquoise, Tanzanite, and Zircon. This trio offers a diverse palette of colors, histories, and properties, ranging from the ancient opaque blue-green of Turquoise to the brilliant fire of Zircon and the modern, velvety violet-blue of Tanzanite. While early birthstone lists designated Ruby for December, the evolution of these lists has culminated in this rich variety, providing December-born individuals with a spectrum of choices that reflect the cool, serene, and transformative nature of the winter season.
The significance of these stones extends beyond mere aesthetics. They represent a confluence of geological rarity, historical lore, and metaphysical belief. Turquoise has served as a protective talisman for millennia, Zircon has been mistaken for diamond due to its high refractive index, and Tanzanite has rapidly ascended from a recent discovery to a global phenomenon. This article explores the geological origins, gemological properties, historical significance, and cultural symbolism of Turquoise, Tanzanite, and Zircon, providing a definitive guide to the birthstones of December.
History and Lore: The Evolution of December’s Gems
The history of December’s birthstones is a timeline of expansion and adaptation. The earliest birthstone lists, rooted in biblical traditions such as the High Priest’s breastplate described in the Book of Exodus, did not associate the modern trio with the month of December. In fact, the earliest historical references suggest Ruby was the designated stone for December. However, as gemology advanced and trade routes expanded, the selection of stones grew.
The modern commercialization of birthstones began in earnest in the 19th century. In 1870, Tiffany & Co. published the "Gregorian Birthstone Poems," which officially listed Turquoise as the birthstone for December. This marked the first major shift away from the ancient lists, establishing Turquoise as the primary stone for the month.
The timeline of official recognition continued to evolve throughout the 20th century: * 1912: The National Association of Jewellers (now Jewellers of America) standardized the list, keeping Turquoise as the primary stone but adding Lapis Lazuli as an alternative. * 1952: The Jewelry Industry Council of America added Zircon to the list, expanding the options beyond the opaque Turquoise. * 2002: The American Gem Trade Association (AGTA) added Tanzanite, acknowledging the stone's rising popularity and commercial significance.
This evolution reflects a desire to offer consumers variety in color, durability, and price. Today, the three stones are often viewed as a collective: Turquoise represents the traditional, Zircon the classic, and Tanzanite the modern.
Turquoise: The Ancient Talisman
Origins and History Turquoise is arguably the oldest gemstone in the December collection, with a history dating back over 5,000 years. The stone derives its name from the French phrase pierre turquoise, meaning "Turkish stone." This nomenclature traces the gem's trade route: it was mined in Persia (modern-day Iran) and transported to Europe through the gem markets of Constantinople (Turkey).
Historical evidence of Turquoise usage is widespread. It was a favored gem for amulets in ancient Egypt, often placed on the mummified remains of royalty to ensure safe passage to the afterlife. The Incas and Mayas offered Turquoise to their gods, while the Native Americans of the American Southwest utilized the stone extensively. For the Pueblo and Navajo peoples, Turquoise was a symbol of youth and strength, often used in rituals and as a currency. In Tibet, the stone was considered a birthstone of fortune, health, and success, and was widely used in jewelry and trade.
Metaphysical Beliefs The lore surrounding Turquoise is rich with protective attributes. It was believed to warn the wearer of approaching illness or danger by changing color, often turning pale when danger was imminent. This "warning stone" property made it a favorite among lovers and married couples, as it was thought to preserve friendship and protect relationships. The stone is associated with the element of Fire (for Sagittarius) and Earth (for Capricorn), and is linked to the planets Jupiter and Saturn.
Gemological Properties Turquoise is an opaque宝石 with a distinctive color range from sky blue to greenish-blue, often containing a "matrix" (veins of the host rock). It is a phosphate mineral, specifically a hydrated phosphate of copper and aluminum.
- Hardness: On the Mohs scale, Turquoise ranks between 5 and 6. This makes it relatively soft compared to other gemstones.
- Durability: It is porous and can be susceptible to chemicals, heat, and sudden temperature changes. It is prone to scratching and can be damaged by cosmetics, perfumes, and even sweat.
- Treatment: Most commercial Turquoise is stabilized or treated with wax or resin to enhance its color and durability.
Tanzanite: The Gem of a Generation
Origins and History Tanzanite is the newest addition to the December family, discovered only in 1967. It is found exclusively in the Merelani district of northern Tanzania, near the base of Mount Kilimanjaro. This singular geographic origin makes it one of the rarest gemstones in the world; geologists estimate that the supply may be depleted within the next few decades.
Tanzanite’s rise to prominence was driven largely by the marketing efforts of Tiffany & Co., which introduced the stone to the global market in 1968. The company recognized the stone's unique violet-blue hue and marketed it heavily, eventually naming it "Tanzanite" after its country of origin.
Gemological Properties Tanzanite is a variety of the mineral zoisite. It is known for its intense, velvety color and strong pleochroism—the ability to display different colors (blue, violet, and red-violet) when viewed from different angles.
- Hardness: It ranks between 6 and 7 on the Mohs scale.
- Durability: While harder than Turquoise, Tanzanite is still considered fragile due to its perfect cleavage in one direction. A sharp blow can cause the stone to split.
- Color: The most prized color is a deep violet-blue, often referred to as "bb" (blue-blue) or "v-b" (violet-blue).
Metaphysical Beliefs Tanzanite is associated with transformation, intuition, and spiritual growth. It is often linked to the "New Age" movement and is believed to facilitate a higher consciousness and a connection to the divine. Its symbolism of new beginnings aligns with its recent discovery and rapid entry into the gemological canon.
Zircon: The Diamond Imposter
Origins and History Zircon is one of the oldest minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. However, the blue variety of Zircon, which is the specific birthstone for December, has a distinct history.
It is crucial to distinguish Zircon from Cubic Zirconia (CZ), a synthetic diamond simulant. Zircon is a natural gemstone, while CZ is a laboratory-created material. Historically, Zircon was highly valued in the Middle Ages for its purported medicinal properties and was believed to induce sleep and ward off evil spirits.
Gemological Properties Blue Zircon is renowned for its brilliance and fire, which rivals that of diamond. It has a high refractive index (1.92–1.98) and strong dispersion.
- Hardness: It ranks between 6.5 and 7.5 on the Mohs scale, making it durable enough for most jewelry types, though care should be taken to avoid hard knocks.
- Color: The blue color is almost always the result of heat treatment. Most brown Zircon is heated to high temperatures to remove the brown hue and produce a blue color. This treatment is stable and permanent.
- Clarity: Zircon often contains inclusions, but high-quality stones are clean and eye-catching.
Metaphysical Beliefs Zircon is associated with wisdom, prosperity, and good fortune. It is believed to promote honor and purity, and is often used as a grounding stone. The blue variety, specifically, is linked to clarity of thought and calmness.
Blue Topaz: The Modern Alternative
While the primary trio consists of Turquoise, Tanzanite, and Zircon, some sources, such as the Gemological Institute of America (GIA), also recognize Blue Topaz as a December birthstone. Its inclusion in some lists reflects its popularity in the modern jewelry market.
Origins and Treatment Topaz is a fluorine aluminum silicate mineral. Natural blue Topaz is extremely rare. The vast majority of blue Topaz on the market is produced by irradiating and heating colorless Topaz. This process is safe and standard in the industry.
Gemological Properties * Hardness: 8 on the Mohs scale, making it very durable and suitable for rings and daily wear. * Color: Ranges from pale Sky Blue to the deep, saturated Swiss Blue and London Blue. * Symbolism: Associated with clarity, communication, and calmness.
Comparative Analysis of December Birthstones
To assist in selecting the right gemstone, the following table summarizes the key properties of the four stones discussed.
| Gemstone | Color & Varieties | Mohs Hardness | Symbolism / Meaning | Durability & Care Notes |
|---|---|---|---|---|
| Turquoise | Sky blue to greenish-blue (often opaque with matrix) | 5 – 6 | Protection, friendship, good fortune | Soft, porous; avoid chemicals, heat, and scratches. |
| Tanzanite | Violet-blue to deep blue (pleochroic) | 6 – 7 | Transformation, intuition, spiritual growth | Fragile due to perfect cleavage; avoid sharp blows. |
| Zircon | Brilliant blue (also multi-color) | 6.5 – 7.5 | Wisdom, prosperity, good fortune | Durable but can be brittle; avoid hard knocks. |
| Blue Topaz | Sky Blue, Swiss Blue, London Blue | 8 | Clarity, communication, calmness | Very durable; stable color from treatment. |
Care and Cleaning
The care required for December birthstones varies significantly based on their hardness and chemical composition.
Turquoise Care Due to its porosity and softness, Turquoise requires the most care. It should be cleaned with warm, soapy water and a soft cloth. Ultrasonic cleaners and steam cleaners are strictly forbidden, as they can strip the stone of its stabilizing treatments and cause cracking. Avoid exposing Turquoise to lotions, cosmetics, and perfumes.
Tanzanite Care Tanzanite should be cleaned with warm, soapy water and a soft brush. While it can be taken to professional jewelers for cleaning, owners should be cautious about ultrasonic cleaners, which can cause the stone to cleave. It is best set in protective settings like bezels for rings, as it is prone to chipping.
Zircon Care Zircon is relatively durable but can be brittle. It is safe to use warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided due to potential thermal shock, which can cause internal fractures.
Blue Topaz Care Blue Topaz is durable and can be cleaned with warm, soapy water, ultrasonic cleaners, and steam cleaners. However, it is susceptible to scratching, so it should be stored separately from harder gemstones like diamonds and sapphires.
Geological Formation and Sources
Turquoise Sources Turquoise forms in arid regions where acidic, copper-rich groundwater percolates through aluminum-bearing rocks. The interaction creates hydrated copper aluminum phosphates that fill fractures and cavities. * Major Sources: Iran (historically the source of the finest "Persian Turquoise"), the United States (Nevada, Arizona, New Mexico), Tibet, and India.
Tanzanite Sources Tanzanite is found exclusively in the Merelani district of Tanzania. The geological conditions required for its formation are unique, involving the metamorphism of calcareous rocks by heat from nearby magma intrusions. The limited geographic area of its occurrence contributes to its rarity.
Zircon Sources Zircon is a common mineral found in igneous, metamorphic, and sedimentary rocks. However, gem-quality blue Zircon is much rarer. * Major Sources: Cambodia, Sri Lanka, and Thailand are known for producing the blue varieties used in jewelry. Australia contains the oldest zircon crystals but these are typically used for geological dating rather than gemstones.
Conclusion
The birthstones of December—Turquoise, Tanzanite, and Zircon—offer a remarkable study in the diversity of the mineral kingdom. From the ancient, protective talisman of Turquoise to the singular, recent discovery of Tanzanite and the ancient, brilliant fire of Zircon, each stone carries a distinct identity. For the December-born, the choice is not merely aesthetic but a connection to history, geology, and symbolism. Whether one values the durability of Zircon, the rarity of Tanzanite, or the cultural weight of Turquoise, the month is well-represented by this cool-toned trio. As the year closes, these stones stand as symbols of clarity, protection, and transformation, perfectly mirroring the reflective nature of the winter season.