For those born in the final month of the year, the question of "the" December birthstone is a surprisingly complex one. Unlike months with a single designated gem, December boasts a quartet of beautiful and distinct stones, each offering a unique shade of blue and a rich history. The traditional birthstone is the classic blue-green Turquoise, but the modern list has expanded to include Tanzanite, Zircon, and Topaz, providing a wide spectrum of choices in color, durability, and value. This abundance is a relatively recent development, driven by a desire to offer consumers more flexibility and variety. The official lists maintained by institutions like the Gemological Institute of America (GIA) and updated by trade organizations reflect this evolution, acknowledging a family of gems that share a common color theme reminiscent of winter skies and icy waters.
This guide will explore each of the four primary December birthstones—Turquoise, Tanzanite, Zircon, and Blue Topaz—in detail. We will delve into their geological origins, gemological properties, historical lore, and their journey to becoming symbols for those born in December. From the ancient amulets of Persia to the modern, scientifically-enhanced gems in today's jewelry market, the story of December's birthstones is one of fascinating diversity.
History and Lore: A Journey Through Time
The history of December's birthstones is a layered narrative of ancient tradition, discovery, and modern standardization. The story begins with Turquoise, the earliest and most traditional of the group.
Turquoise: The Ancient Amulet Turquoise is arguably one of the oldest gemstones known to humanity, with a history spanning thousands of years. Its name is a testament to its long journey from its mining origins to European markets. The name "Turquoise" derives from the French phrase pierre turquoise, meaning "stone of Turkey." This name was bestowed because the gem was first brought to Europe from the gem markets of Constantinople (modern-day Istanbul) by Turkish traders. The stone itself, however, was not mined in Turkey. Its primary sources were in Persia (modern-day Iran) and along the Sinai Peninsula.
From the earliest times, Turquoise was a favored gem for amulets and talismans. Its relative softness and opacity made it easy to cut into various shapes and to inscribe with protective symbols. Ancient cultures attributed powerful properties to the stone. It was widely believed to offer protection against danger and to bring good fortune and success. The gem was particularly prized by lovers and married couples, who saw it as a protector of relationships and a preserver of friendship when given as a gift. A notable folk belief held that the stone could warn its wearer of impending illness or danger by changing its color to a pale hue.
Different cultures developed their own unique relationships with Turquoise. The Tibetans considered it a birthstone of fortune, health, and success, and it was so valued that it was often used as a form of currency. In the Americas, the ancient Incas and Mayas offered turquoise as a gift to their gods, while the Native American tribes of the Southwest associated the gem with youth and strength.
The Modern List: Standardization and Expansion The list of birthstones we recognize today is largely a product of 20th-century commercial standardization. In 1912, the National Association of Jewelers in the United States sought to formalize the unofficial list of birthstones, combining historical customs with gems that were practical for jewelry companies to sell and market. At this time, Turquoise and Zircon were the recognized stones for December.
The list continued to evolve. In 1952, the Jewelry Industry Council of America updated the list, adding Zircon as another official December gemstone. The most significant recent addition came in 2002, when Tanzanite was added to the list by the American Gem Trade Association (AGTA). The reason December has such a large number of birthstones is not definitively known, but it is widely believed to be a deliberate choice to provide more affordable and durable options for consumers. This expansion offers greater flexibility in price, durability, and personal style. Blue Topaz, while not always on the most formal lists, has gained immense popularity as an alternative and is now frequently considered a mainstream December birthstone due to its beauty, durability, and affordability.
Geological Formation and Sources
Each of the four December birthstones forms under unique geological conditions, leading to their distinct characteristics and appearances.
Turquoise Turquoise is an opaque, hydrous phosphate of copper and aluminum. It is a secondary mineral formed when water containing copper and aluminum seeped through pre-existing rock. In arid regions, this water evaporates, leaving behind deposits of turquoise. The presence of copper is what gives the stone its signature blue to green color; the more copper, the bluer the stone. The dark veins and web-like patterns often seen in turquoise are pieces of the surrounding host rock, known as matrix, which became embedded in the gem during its formation. Historically, the most significant sources have been in Persia (Iran) and the Sinai Peninsula, but today, major commercial deposits are also found in the United States (particularly Arizona and New Mexico), China, and Mexico.
Tanzanite Tanzanite is an extremely rare gemstone found in only one location on Earth: a small, four-square-kilometer mining area in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. This single-source origin makes it thousands of times rarer than diamond. Tanzanite is a variety of the mineral zoisite and is formed by the intense heat and pressure of tectonic plate movement in the East African Rift Valley. The gem is typically a brownish color in its natural state; the vibrant violet-blue hue for which it is famous is almost always the result of a controlled heating process that removes the brownish tones and saturates the blue and violet colors.
Zircon Zircon is one of the world's oldest minerals, with crystals found in Australia that are over 4.4 billion years old. It is a naturally occurring zirconium silicate. Blue zircon, the variety popular for December, is typically created by heating the common brown zircon crystal to very high temperatures. This heat treatment, which can also occur naturally, removes the brown color and produces the desired blue hue. Major sources for zircon include Australia, Cambodia, Sri Lanka, and Thailand.
Blue Topaz Topaz is a silicate mineral of aluminum and fluorine. Naturally occurring blue topaz is exceptionally rare. The vibrant blue topaz seen in the jewelry market today is almost always the product of irradiation and heat treatment of colorless or pale topaz. The process involves exposing the stone to high-energy radiation, which alters its crystal lattice to produce a blue color, followed by heating to stabilize the color and achieve the desired shade. The main sources for this treated blue topaz are Sri Lanka, Brazil, Mexico, Nigeria, and the United States. Notably, Blue Topaz is the official state gem of Texas.
Gemological Properties
Understanding the physical and chemical properties of these gems is crucial for appreciating their value and for their proper care. The following table summarizes the key gemological data for each of the four December birthstones, based on the provided information.
| Gemstone | Chemical Composition | Hardness (Mohs Scale) | Key Characteristics |
|---|---|---|---|
| Turquoise | Hydrous phosphate of copper and aluminum | Varies (approx. 5-6) | Opaque; color from blue to green due to copper; often contains matrix (host rock). |
| Tanzanite | Calcium aluminum silicate hydroxide | 6.5 - 7 | Trichroic (shows blue, violet, and burgundy); color is almost always enhanced by heating. |
| Zircon | Zirconium silicate | 7.5 | High refractive index and brilliance; blue color is typically achieved through heat treatment of brown zircon. |
| Blue Topaz | Aluminum silicate fluoride hydroxide | 8 | Transparent; blue color is almost always the result of irradiation and heat treatment of colorless topaz. |
Durability and Wearability For jewelry intended for everyday wear, such as engagement rings, durability is a primary concern. As shown in the table, Blue Topaz is the hardest and most durable of the four, with a Mohs hardness of 8, making it highly resistant to scratching and abrasion. Zircon, at 7.5, is also quite durable, though it can be more brittle due to its crystal structure. Tanzanite (6.5-7) and Turquoise (approx. 5-6) are softer and more susceptible to damage. Turquoise is also porous and can be damaged by chemicals, lotions, and even the natural oils of the skin, which can cause discoloration over time. For these reasons, Blue Topaz and Zircon are often recommended for pieces that will see frequent use, while Turquoise and Tanzanite require more care.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these gems have been imbued with deep symbolic meaning and metaphysical beliefs, many of which persist today.
Turquoise: Protection and Fortune As detailed in historical lore, Turquoise is a stone of protection, good fortune, and emotional balance. It has been called the "sky stone" by ancient cultures, believed to connect the wearer to the heavens. It is traditionally associated with calming energies, fostering serenity, and bringing wealth and happiness. Its reputation as a stone that protects relationships and preserves friendship makes it a popular gift among friends and partners.
Tanzanite: Transformation and Intuition A much more modern addition, Tanzanite has quickly acquired its own set of symbolic meanings. Its unique and powerful trichroism—showing blue, violet, and burgundy hues—is often linked to a higher consciousness and intuition. It is considered a stone of transformation, helping to guide individuals through changes with a calm and clear mind. Its vibrant energy