December, the final month of the year, is uniquely adorned with a collection of four gemstones that capture the essence of winter in their cool, evocative blue hues. These gemstones—turquoise, tanzanite, zircon, and blue topaz—are not only celebrated for their visual beauty but also for the rich histories, symbolic meanings, and gemological properties that make them distinctive. Each has a story to tell, from ancient traditions to modern commercialization, and their inclusion in the December birthstone list reflects both their rarity and their cultural significance.
This article explores the four December birthstones in detail, examining their origins, historical uses, gemological characteristics, and the meanings attributed to them. Whether you are a gemstone enthusiast, a jewelry buyer, or simply curious about the treasures associated with December, this guide offers a comprehensive look into the world of these captivating stones.
History and Lore of December Birthstones
December’s birthstones are a fascinating blend of ancient tradition and modern innovation. Unlike most months, which are associated with a single gemstone, December has been historically linked to multiple stones, with the list evolving over time. The earliest known birthstone list, dating back to the 10th century, included ruby as the December stone. However, the modern December birthstone list has seen several additions and revisions.
The Evolution of December’s Birthstone List
The current list of December birthstones has been shaped by a combination of historical tradition and commercial influence. In 1870, turquoise was designated as the December birthstone in the "Gregorian Birthstone Poems" pamphlet by Tiffany & Co. This designation was later adopted by the National Association of Jewellers (now the Jewellers of America) in 1912, which listed turquoise as the primary December birthstone and lapis lazuli as an alternative.
In 1952, zircon was added to the list by the Jewelry Industry Council of America, and in 2002, tanzanite joined the group, bringing the total to four. Blue topaz was also included in some modern lists, particularly in the United States, where it is the official state gem of Texas and is mined in several countries including Sri Lanka, Brazil, Mexico, Nigeria, and the U.S.
The inclusion of multiple gemstones for December is often attributed to a desire to offer a wider range of color, hardness, and affordability. This diversity allows individuals to choose a birthstone that aligns with their personal preferences and lifestyle.
Ancient and Cultural Significance
Each of December’s birthstones has a unique historical background and cultural significance:
- Turquoise is one of the oldest known gemstones, dating back to ancient Egypt, where it was used in burial masks and amulets. It was also highly valued by Native American cultures, who used it in ceremonial jewelry and healing practices.
- Tanzanite, the most recent addition to the list, was discovered in 1967 in Tanzania, near Mount Kilimanjaro. Named after the country, it is a rare variety of zoisite and is known for its trichroism, appearing blue, purple, or burgundy depending on the viewing angle.
- Zircon, particularly the blue variety, has been used in jewelry and spiritual practices for centuries. It is believed to promote wisdom, balance, and clarity.
- Blue topaz, while relatively new to the birthstone list, has been found in historical records and is appreciated for its durability and vibrant color.
The shared blue palette of these gemstones reflects the winter season and the icy, tranquil mood of December. This thematic consistency is what binds these diverse stones into a cohesive group.
Geological Formation and Sources of December Birthstones
Understanding the geological formation and sources of December’s birthstones provides insight into their rarity, durability, and unique properties. Each gemstone forms under specific conditions and is found in distinct locations around the world.
Turquoise
Turquoise is a phosphide mineral that forms in anhydrous environments, typically as a secondary mineral in the weathering of phosphorus-bearing minerals. It is commonly found in copper-rich deposits, where it takes on its characteristic sky-blue to greenish-blue color due to the presence of copper and aluminum.
The most notable sources of high-quality turquoise include:
- Nevada, USA – Known for its "Nevada Blue" and "Sleeping Beauty" turquoise.
- Iran – Historically one of the most important sources, producing the "Persian Blue" variety.
- China – A major modern source, particularly for dyed turquoise.
Turquoise is relatively soft with a Mohs hardness of 5–6, making it fragile and prone to damage. It also has porosity, meaning it can absorb liquids and oils. This makes it important to handle with care and avoid exposure to harsh chemicals.
Tanzanite
Tanzanite is a rare variety of zoisite, a calcium aluminum silicate with a trichroic nature. It was first discovered in 1967 in Tanzania, near Mount Kilimanjaro, and is found only in a small area of less than 500 square kilometers.
The formation of tanzanite is linked to metamorphic processes, where zoisite was transformed under high pressure and heat to develop its violet-blue color. This limited geographic source contributes to its rarity and high value.
Due to its fragile structure and vulnerability to heat and light, tanzanite is often heat-treated to enhance its color and stability. It has a Mohs hardness of 6–7, making it suitable for occasional wear but not for daily use.
Zircon
Zircon, a zirconium silicate mineral, occurs in a variety of colors, including colorless, yellow, red, and blue. The blue variety, known as "star blue zircon", is the most popular for jewelry.
Zircon is found in igneous and metamorphic rocks, and notable sources include:
- Australia – A major source of blue zircon.
- Madagascar – Known for producing high-quality zircon in various colors.
- Brazil – A source of yellow and red zircon.
Zircon has a Mohs hardness of 6.5–7.5, making it more durable than turquoise and tanzanite. However, it is cleavage-prone, so it should be handled with care, especially in ring settings.
Blue Topaz
Blue topaz is a silicate mineral that occurs naturally in colorless or yellow forms. The blue color is achieved through irradiation or heat treatment, which alters the atomic structure of the stone.
Blue topaz is found in several countries, including:
- Brazil – A major source of topaz in various colors.
- Mexico – Known for high-quality blue topaz.
- Sri Lanka – Produces colorless topaz, which is often treated to achieve blue hues.
Blue topaz has a Mohs hardness of 8, making it one of the most durable December birthstones and suitable for everyday wear. It is also resistant to heat and light, making it easier to maintain compared to tanzanite and turquoise.
Gemological Properties of December Birthstones
Each of December’s birthstones has its own set of gemological properties that define its beauty, durability, and value. Understanding these properties is essential for buyers, jewelers, and collectors.
Turquoise
- Chemical Formula: CuAl₆(PO₄)₄(OH)₈·4H₂O
- Color: Sky-blue to greenish-blue
- Hardness (Mohs Scale): 5–6
- Luster: Waxy to dull
- Specific Gravity: 2.6–2.8
- Refractive Index: 1.61–1.65
Turquoise is porous and absorbs liquids, so it must be sealed with resin or wax to enhance durability and color. It is not suitable for daily wear due to its softness and fragility.
Tanzanite
- Chemical Formula: Ca₂Al₃(SiO₄)₃(OH)
- Color: Violet-blue, purple, or burgundy (depending on viewing angle)
- Hardness (Mohs Scale): 6–7
- Luster: Vitreous
- Specific Gravity: 3.1–3.4
- Refractive Index: 1.694–1.701
Tanzanite is known for its trichroism, which allows it to display three different colors when viewed from different angles. It is rare and valuable, especially in even colors and large sizes.
Zircon
- Chemical Formula: ZrSiO₄
- Color: Colorless, yellow, red, blue (most popular for jewelry)
- Hardness (Mohs Scale): 6.5–7.5
- Luster: Vitreous to adamantine
- Specific Gravity: 4.6–4.7
- Refractive Index: 1.92–2.01
Zircon is optically brilliant and often mistaken for diamonds or cubic zirconia due to its sparkling appearance. It is treated to enhance its blue color, and heat treatment can also change its color to golden or reddish tones.
Blue Topaz
- Chemical Formula: Al₂SiO₆
- Color: Blue (often enhanced through irradiation or heat treatment)
- Hardness (Mohs Scale): 8
- Luster: Vitreous
- Specific Gravity: 3.4–3.6
- Refractive Index: 1.62–1.64
Blue topaz is one of the hardest December birthstones, making it ideal for everyday jewelry. It is resistant to heat and light, which makes it low-maintenance and long-lasting.
Symbolism and Metaphysical Beliefs of December Birthstones
The December birthstones are not only admired for their beauty but also for the symbolism and metaphysical properties attributed to them. These beliefs have evolved over time, shaped by cultural traditions, spiritual practices, and modern interpretations.
Turquoise
Turquoise has long been associated with protection, healing, and spiritual guidance. In ancient Egypt, it was used in burial masks and amulets to protect the deceased in the afterlife. Native American tribes, particularly the Navajo and Pueblo, valued turquoise for its healing properties and used it in ceremonial jewelry and medicine.
Modern metaphysical beliefs attribute calming and grounding effects to turquoise, making it a popular choice for those seeking emotional stability and mental clarity. Some also believe it enhances communication and self-expression.
Tanzanite
Tanzanite is often associated with transformation, intuition, and spiritual growth. Its violet-blue color is believed to stimulate the third eye and crown chakras, promoting self-awareness and a deeper connection to the universe.
In modern spiritual practices, tanzanite is used to assist with emotional healing, especially in times of change or transition. It is also thought to enhance creativity and imagination, making it a favored stone among artists and writers.
Zircon
Zircon, especially the blue variety, is known for its clarity and wisdom. It is believed to help clarify thoughts, enhance memory, and improve decision-making. In ancient times, zircon was used in amulets and talismans to ward off negative energies and attract positive ones.
Modern interpretations suggest that zircon promotes inner balance and emotional stability, making it a stone of renewal and transformation. It is also considered a stone of the heart, supporting love and compassion.
Blue Topaz
Blue topaz is often associated with calmness, serenity, and emotional healing. It is believed to soothe the mind, reduce stress, and promote a sense of peace. In spiritual practices, blue topaz is used to open the heart and throat chakras, encouraging honest communication and emotional expression.
It is also considered a stone of success and abundance, believed to attract opportunities and financial stability. This makes it a popular choice for those seeking clarity and confidence in their personal and professional lives.
Care and Cleaning of December Birthstones
Proper care and cleaning are essential to maintain the beauty and longevity of December birthstones. Each gemstone requires specific handling due to differences in hardness, porosity, and sensitivity to light and heat.
Turquoise
- Avoid exposure to water and moisture for long periods, as it can damage the sealant and alter the color.
- Do not use harsh chemicals or abrasive cleaners, as they can damage the surface.
- Store in a dry, cool place to prevent cracking or discoloration.
- Clean with a soft cloth and mild soap if necessary.
Tanzanite
- Avoid exposure to direct sunlight for prolonged periods, as it can fading the color.
- Heat is also a concern, so avoid using heat-based tools during jewelry repairs.
- Clean with a soft brush and warm, soapy water, then dry with a lint-free cloth.
- Store in a soft pouch or jewelry box to prevent scratches.
Zircon
- Avoid exposure to sudden temperature changes, as it can cause cracking.
- Use a soft brush and warm, soapy water to clean the stone.
- Avoid ultrasonic cleaners, as they can damage the structure of the gem.
- Store in a separate compartment to prevent scratching from other gemstones.
Blue Topaz
- Blue topaz is one of the most durable December birthstones, with a Mohs hardness of 8, making it suitable for everyday wear.
- Clean with a soft brush, warm soapy water, and a lint-free cloth.
- Avoid using ultrasonic or steam cleaners, as they may damage the stone in exceptionally rare cases.
- Store in a dry, secure place to prevent scratches.
Conclusion
December is a month of celebration, reflection, and renewal, and its four birthstones—turquoise, tanzanite, zircon, and blue topaz—capture the essence of winter with their cool, blue hues. Each gemstone carries a unique history, set of properties, and symbolic meaning, making them not only beautiful but also rich in cultural and spiritual significance.
From the ancient Egyptian turquoise to the modern discovery of tanzanite, these stones offer a connection to the past and a glimpse into the future. Whether you choose a soft, sky-blue turquoise for its calming effect or a deep, violet-blue tanzanite for its transformative energy, there is a December birthstone to match every personality and purpose.
Understanding the geology, history, and care of these gemstones allows you to appreciate their value and make informed decisions when selecting birthstone jewelry. With their rich colors, symbolic meanings, and diverse properties, December’s birthstones are a true celebration of the final month of the year.