December stands unique in the calendar of birthstones, boasting not one or two, but four officially recognized gemstones. This abundance sets it apart, offering individuals born in the final month of the year a rare and compelling choice. The four gems—Turquoise, Tanzanite, Blue Topaz, and Blue Zircon—are united by a common chromatic theme: the cool, serene blues that evoke the winter sky and icy landscapes. Each stone, however, possesses its own distinct history, geological origin, and set of gemological properties, contributing to a rich tapestry of symbolism and value. The evolution of December’s birthstone list reflects the dynamic nature of both gemological discovery and commercial tradition, making it a fascinating subject for enthusiasts, collectors, and jewelry buyers alike. This article delves into the history, formation, properties, and significance of these four remarkable blue gems, drawing exclusively from authoritative sources to provide a comprehensive overview.
History and Lore: The Evolution of a Month's Gems
The tradition of assigning gemstones to specific months has ancient roots, believed to have originated in Mesopotamia and later adopted by the Greeks and Romans. The December birthstone list, in particular, has undergone significant changes over the centuries. Initially, the month was associated with only two stones: Turquoise and Zircon. Turquoise, one of the oldest known birthstones, has been cherished for millennia. Historical records indicate it was a prized possession of royalty, such as King Tut, who was interred with turquoise artifacts. Ancient cultures believed the stone offered protection from harm, including falls and negative energy, and it was often worn as an amulet.
Zircon, while also historically significant, has a different legacy. It is a gem with incredible sparkle, often mistaken for diamond throughout history due to its high refractive index. Its inclusion in the original December list speaks to its long-standing value in jewelry and adornment.
The 20th century marked a period of expansion for the December birthstones. In 1912, the National Association of Jewelers in the United States standardized an unofficial list, blending historical customs with gemstones that were practical for jewelry companies to sell. This list was later updated by the Jewelry Industry Council of America in 1952, which added Blue Topaz to December’s options. Blue Topaz’s rise in popularity was driven by its durability and the ability to produce large, vividly blue stones, making it an attractive and affordable choice for modern jewelry.
The most recent addition to the December family came in 2002, when Tanzanite was officially recognized. This decision was prompted by the gem’s rapid rise in popularity following its discovery in the 1960s. Tanzanite’s inclusion reflects the birthstone tradition’s capacity to evolve with new gemological discoveries and commercial offerings. Today, the Gemological Institute of America (GIA) lists Turquoise, Tanzanite, and Zircon as December’s birthstones, with Blue Topaz now frequently treated as a mainstream fourth option. This expansion offers consumers greater flexibility in terms of price, durability, and personal style, a trend particularly noted in the U.S. market where affordability and variety are highly valued.
Geological Formation and Sources
The four December birthstones originate from vastly different geological environments, which directly influences their rarity, availability, and value.
Turquoise is a secondary mineral formed in arid regions where water interacts with copper-rich rocks. The presence of copper gives turquoise its characteristic blue to green color, while the specific geological conditions and weathering processes create its unique matrix—the web-like patterns of host rock that remain within the gem. Significant sources include the southwestern United States (notably Arizona and New Mexico), Iran, Egypt, China, Mexico, and parts of Central Asia and Africa. Its formation is relatively rare, requiring a precise combination of geological factors.
Tanzanite is the rarest of the four, with a geological origin that is extraordinarily limited. It is a variety of the mineral zoisite and is mined exclusively in a specific, small region of Tanzania, near Mount Kilimanjaro. This geographic restriction is the primary reason for its rarity and high value. The gem’s formation is linked to the tectonic activity that shaped the East African Rift, creating unique conditions for the crystallization of zoisite containing vanadium, which gives tanzanite its signature violet-blue hue.
Blue Topaz is a variety of the mineral topaz, which forms in igneous rocks like granite and rhyolite. Unlike tanzanite, topaz is found in multiple locations worldwide. Major sources include Sri Lanka, Brazil, Mexico, Nigeria, and the United States (where it is the official state gem of Texas). Its relative abundance compared to tanzanite and turquoise contributes to its more accessible price point. It is important to note that most blue topaz in the market is colorless topaz that has been irradiated and heat-treated to achieve its blue color, a standard industry practice.
Blue Zircon is the oldest of the four in terms of geological age, often found in placer deposits (sediments concentrated by water action) derived from ancient igneous rocks. It is mined in several countries, including Cambodia, Myanmar, Sri Lanka, Thailand, and Australia. Zircon is a durable mineral, but natural blue zircon is quite rare. Most blue zircon in the gem trade is heat-treated brown zircon to achieve its blue color. The gem’s high dispersion (fire) and refractive index make it a brilliant stone, but its relative scarcity compared to blue topaz affects its market positioning.
Gemological Properties: A Comparative Analysis
Understanding the physical and optical properties of these gems is crucial for both appreciation and care. The table below summarizes key gemological characteristics based on the provided sources.
| Gemstone | Typical Color Range | Hardness (Mohs Scale) | Key Properties & Notes |
|---|---|---|---|
| Turquoise | Light blue to greenish-blue, often with a matrix. | 5 - 6 | Relatively soft and porous; requires careful handling. Often treated with wax or resin to enhance stability and color. |
| Tanzanite | Deep bluish violet to violet-blue. | 6.5 - 7 | Pleochroic (shows different colors from different angles). Relatively soft for a gemstone, requiring protective settings. |
| Blue Topaz | Light sky blue to deep Swiss blue. | 8 | The hardest and most durable of the December birthstones, making it ideal for everyday wear, including engagement rings. |
| Blue Zircon | Light to deep blue, sometimes with greenish hues. | 6.5 - 7.5 | Known for its high refractive index and strong dispersion (fire), giving it exceptional brilliance. |
Turquoise has the lowest hardness on the Mohs scale, ranging from 5 to 6. This makes it susceptible to scratches and damage from chemicals, heat, and abrasion. Its porous nature means it can absorb oils and liquids, which can lead to discoloration or cracking. Consequently, turquoise jewelry should be handled with care and is not typically recommended for daily, heavy wear.
Tanzanite is slightly harder, with a Mohs hardness of 6.5 to 7. While more durable than turquoise, it is still relatively soft for a gemstone and can be prone to chipping or cracking if impacted. Its defining gemological feature is pleochroism, where the stone exhibits different shades of blue and violet depending on the viewing angle. This property is often leveraged by gem cutters to maximize the stone’s color in finished jewelry.
Blue Topaz is the most durable of the four, with a Mohs hardness of 8. This high hardness makes it resistant to scratching and suitable for everyday wear, including engagement rings—a recommendation noted by many U.S. jewelry brands. Its color is typically achieved through treatment, but the resulting stones are stable and popular for their vivid, consistent blue hues.
Blue Zircon has a hardness of 6.5 to 7.5, making it reasonably durable, though it can be brittle. Its most notable optical properties are a high refractive index (2.0) and strong dispersion (0.039), which is higher than that of diamond. This gives blue zircon a fiery sparkle that is highly prized. Like blue topaz, most blue zircon in the market is the result of heat treatment applied to brown zircon crystals.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, each of these December birthstones has accumulated a wealth of symbolic meaning and metaphysical beliefs, often linked to their color and historical use.
Turquoise is perhaps the most symbolically rich of the four. For millennia, it has been regarded as a stone of protection, wisdom, and good fortune. Ancient cultures believed it could shield the wearer from falls and negative energy. In many traditions, turquoise symbolizes tranquility, friendship, and spiritual grounding. Its connection to the sky and water imbues it with calming, healing properties in metaphysical lore. The stone’s matrix patterns are sometimes seen as a map of the universe or a connection to the earth.
Tanzanite, as a modern discovery, has quickly developed its own symbolic narrative. It is often associated with transformation, intuition, and spiritual awakening. Its unique blue-violet color is linked to the crown chakra, believed to facilitate higher consciousness and communication with the spiritual realm. Some sources suggest it promotes calmness and clarity of mind, making it a stone for meditation and self-discovery. Its rarity is also tied to the idea of a once-in-a-lifetime opportunity, resonating with its exclusive geographic origin.
Blue Topaz carries connotations of calm, clarity, and communication. Its clear blue color is associated with the throat chakra, believed to aid in truthful expression and harmonious communication. In metaphysical traditions, blue topaz is thought to soothe emotions, reduce stress, and promote mental clarity. It is also linked to love and good fortune, making it a popular gift. Its durability is symbolically connected to resilience and steadfastness.
Blue Zircon, with its brilliant fire, is often associated with wisdom, wealth, and purity. Historically, it was believed to promote prosperity and honor. Its sparkle is linked to the light of the stars, connecting it to celestial guidance and divine wisdom. In some beliefs, zircon is a protective stone that wards off negative energies and encourages a positive, optimistic outlook. Its association with clarity and focus makes it a stone for those seeking knowledge and spiritual growth.
Care and Cleaning: Preserving Your December Gems
Given their diverse properties, the care required for each December birthstone varies significantly. Proper maintenance is essential to preserve the beauty and integrity of the jewelry.
Turquoise requires the most delicate handling. Due to its softness and porosity, it should be protected from scratches, chemicals, perfumes, and extreme temperatures. Clean turquoise jewelry with a soft, damp cloth only; avoid ultrasonic cleaners, steam cleaners, and harsh detergents. It is advisable to store turquoise pieces separately to prevent contact with harder gems. Periodic professional cleaning and re-polishing may be necessary to maintain its luster.
Tanzanite should be handled with care to avoid impacts. While it can be cleaned with warm water, mild soap, and a soft brush, it is best to avoid ultrasonic cleaners and sudden temperature changes, which can cause cracking. Due to its relative softness, tanzanite jewelry is often set in protective settings like bezels, especially for rings. Professional cleaning is recommended for intricate pieces.
Blue Topaz, being the hardest of the four, is the most resilient. It can be cleaned using standard methods: warm soapy water, a soft brush, and even an ultrasonic cleaner (though caution is advised if the stone has fractures or the jewelry contains other sensitive materials). It is also safe for steam cleaning. Its durability makes it low-maintenance and ideal for daily wear, but it should still be stored separately to avoid scratching other gems.
Blue Zircon is durable but can be brittle. It is generally safe to clean with warm, soapy water and a soft brush. However, ultrasonic cleaners and steam cleaners are not recommended, as the vibrations and heat can potentially cause fractures in the stone. Sudden temperature changes should be avoided. Like tanzanite, zircon benefits from protective settings in rings to prevent chipping.
In all cases, it is prudent to consult with a professional jeweler for specific care instructions, especially for pieces that combine multiple gemstones or delicate settings. For online purchases, buyers are advised to choose sellers with clear return policies, customer reviews, and certificates or gem reports that disclose any treatments the stones may have undergone.
Conclusion
The four birthstones of December—Turquoise, Tanzanite, Blue Topaz, and Zircon—offer a remarkable diversity of choice, united by the serene beauty of blue. From the ancient, protective talisman of turquoise to the modern, transformative allure of tanzanite, each gem carries a unique story of geological formation, historical significance, and cultural symbolism. Their varying levels of durability, from the soft and porous turquoise to the hard and resilient blue topaz, cater to different lifestyles and preferences, making the December birthstone selection a deeply personal one. The evolution of this list, from a traditional pair to a quadruple crown, mirrors the ongoing journey of gemology and market dynamics, ensuring that every individual born in the winter month can find a stone that resonates with their personal style and story. Whether chosen for its metaphysical properties, its historical depth, or simply its captivating color, a December birthstone is a timeless emblem of the season’s quiet elegance and enduring sparkle.