December, the final month of the calendar year, is associated with a remarkable diversity of birthstones—five in total—each offering a unique blend of beauty, symbolism, and historical significance. Among these, blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise stand out as the most recognized and celebrated. This article explores the properties, origins, and meanings of these December birthstones, drawing from historical records, cultural practices, and scientific data to provide a comprehensive understanding of their allure and importance.
History and Lore of December Birthstones
The tradition of birthstones dates back to ancient times, with early references found in the Biblical Breastplate of Aaron, which listed twelve gemstones, one for each tribe of Israel. While the original list did not include the modern December birthstones, many of these early gemstone associations laid the foundation for later cultural interpretations. Over the centuries, as trade routes expanded and new gemstones were discovered, the list of birthstones evolved, and December eventually gained multiple gemstones—some traditional, others modern.
Ancient Associations
In ancient times, ruby was associated with December. According to the earliest recorded lists, ruby was believed to sharpen the mind, improve concentration, and encourage courtly love. This association, however, is not widely reflected in modern December birthstone lists, and ruby is now more commonly linked to July.
By the 19th century, the turquoise had become a prominent December birthstone, especially in Western cultures. Its association with December can be traced to Tiffany & Co., which in 1870 included it in a "Gregorian Birthstone Poems" pamphlet. Turquoise was also used by ancient shamans and believed to offer protection, prosperity, and good fortune.
In 1912, the National Association of Jewellers (now known as the Jewellers of America) listed turquoise as the primary December birthstone and lapis lazuli as an alternative. Lapis lazuli had been revered since antiquity for its deep blue color and was associated with wisdom and royalty.
In 1952, zircon was added to the list of December birthstones by the Jewelry Industry Council of America. Zircon, particularly in its blue variety, was praised for its brilliance and clarity. It was seen as a natural replacement for lapis lazuli and offered a wider range of color and availability.
Finally, in 2002, tanzanite was officially recognized as a December birthstone in the United States. Tanzanite, a relatively modern gemstone discovered in 1967 in Tanzania, was valued for its unique blue to violet hues and its rarity.
Cultural Significance
Across various cultures, December birthstones have been imbued with symbolic meanings. In Tibetan tradition, onyx was considered a December birthstone and was believed to offer self-mastery and protective energy. In Russia, chrysoprase was the traditional December birthstone and was thought to mend broken hearts and remove inferiority complexes.
In ancient Egypt and Mesopotamia, lapis lazuli was highly prized for its deep blue color and was often used in royal regalia and religious artifacts. It was associated with truth, enlightenment, and wisdom. In Native American cultures, turquoise was a sacred stone, used in rituals and as a symbol of protection and spiritual connection.
These diverse cultural associations highlight the enduring appeal of December birthstones and their ability to transcend geographical and temporal boundaries.
Geological Formation and Sources
Each December birthstone has a unique geological origin and source, shaped by the Earth's complex processes over millions of years.
Blue Zircon
Zircon is one of the oldest minerals on Earth, with some specimens dating back over 4 billion years. It is formed in igneous and metamorphic rocks and is commonly found in granite, basalt, and sedimentary deposits. The blue coloration of zircon is the result of a heat treatment that alters the mineral's structure and enhances its color.
Sources: Zircon is found in a variety of locations around the world, including Australia, Brazil, Cambodia, India, and Thailand. The blue variety is often sourced from Cambodia and Thailand, where it is heat-treated to achieve its vibrant blue hue.
Blue Topaz
Topaz is a silicate mineral that forms in pegmatite and rhyolite rocks. The blue color of topaz is typically the result of irradiation treatment, which alters the crystal structure and creates a stable blue color. Naturally occurring blue topaz is extremely rare.
Sources: The majority of blue topaz is mined in Brazil, particularly in the state of Minas Gerais. Other notable sources include Nigeria and the United States, where topaz is found in deposits in Colorado and Texas.
Tanzanite
Tanzanite is a relatively modern gemstone, first discovered in 1967 in the Merelani Hills of Tanzania, near Mount Kilimanjaro. It is a variety of the mineral columbite, and its striking blue to violet color is due to the presence of vanadium and the effects of heat treatment.
Sources: Tanzanite is found exclusively in Tanzania, making it one of the rarest gemstones in the world. The Merelani Hills are the only known source of this gemstone, and the limited supply has contributed to its high value and exclusivity.
Lapis Lazuli
Lapis lazuli is a metamorphic rock composed primarily of lazurite, with smaller amounts of pyrite, calcite, and other minerals. It is formed under high pressure and temperature conditions, typically in regions with extensive tectonic activity.
Sources: The most famous source of lapis lazuli is Afghanistan, where it has been mined for thousands of years. Other notable sources include Russia, Pakistan, and Chile. The lapis lazuli found in Afghanistan is particularly prized for its deep blue color and high-quality pyrite inclusions.
Turquoise
Turquoise is a hydrated phosphate of aluminum and copper, formed in the oxidation zone of copper deposits. It is typically found in arid regions where water percolates through the rock and deposits copper and aluminum.
Sources: The most famous historical sources of turquoise are in the American Southwest, particularly in Arizona and New Mexico. In ancient times, Egypt and Persia were also major sources. Today, turquoise is also mined in China, Iran, and Mexico, with each location producing stones with distinct colors and patterns.
Gemological Properties
Understanding the gemological properties of each December birthstone is essential for appreciating their beauty and durability. These properties include hardness, refractive index, specific gravity, and optical characteristics, which are important for both gemologists and jewelry buyers.
| Gemstone | Color | Hardness (Mohs) | Refractive Index | Specific Gravity | Optical Characteristic |
|---|---|---|---|---|---|
| Blue Zircon | Blue | 6–7.5 | 1.92–2.01 | 4.6–4.7 | High dispersion, double refraction |
| Blue Topaz | Blue | 8 | 1.62–1.64 | 3.4–3.6 | Single refraction |
| Tanzanite | Blue to violet | 6–7 | 1.69–1.70 | 3.0–3.4 | Strong pleochroism |
| Lapis Lazuli | Blue with white, gold | 5–6 | 1.62–1.64 | 2.4–2.9 | Opaque, chatoyance or asterism |
| Turquoise | Blue to green | 5–6 | 1.61–1.65 | 2.6–2.8 | Opaque, sometimes with matrix patterns |
Blue Zircon
- Hardness: 6–7.5 on the Mohs scale
- Color: Blue (often enhanced by heat treatment)
- Refractive Index: 1.92–2.01
- Specific Gravity: 4.6–4.7
- Optical Properties: High dispersion and double refraction give zircon a "fiery" appearance. However, its double refraction can sometimes make it appear less brilliant when viewed from certain angles.
Blue Topaz
- Hardness: 8 on the Mohs scale
- Color: Blue (naturally rare; most are irradiated)
- Refractive Index: 1.62–1.64
- Specific Gravity: 3.4–3.6
- Optical Properties: Single refraction and good clarity make blue topaz a durable and attractive gemstone.
Tanzanite
- Hardness: 6–7 on the Mohs scale
- Color: Blue to violet (strong pleochroism)
- Refractive Index: 1.69–1.70
- Specific Gravity: 3.0–3.4
- Optical Properties: Strong pleochroism means that tanzanite can appear different colors depending on the angle of view. This characteristic adds to its allure and complexity.
Lapis Lazuli
- Hardness: 5–6 on the Mohs scale
- Color: Deep blue with white and gold inclusions
- Refractive Index: 1.62–1.64
- Specific Gravity: 2.4–2.9
- Optical Properties: Lapis lazuli is an opaque stone, often with a chatoyant or asterism effect due to the alignment of pyrite inclusions.
Turquoise
- Hardness: 5–6 on the Mohs scale
- Color: Blue to green
- Refractive Index: 1.61–1.65
- Specific Gravity: 2.6–2.8
- Optical Properties: Opaque with a waxy to greasy luster. Turquoise often contains matrix patterns, which are natural inclusions that add to its uniqueness.
These properties not only define the gemstones' appearance and durability but also influence their use in jewelry and their care requirements.
Symbolism and Metaphysical Beliefs
December birthstones have been attributed with various symbolic meanings and metaphysical properties across different cultures and historical periods. These beliefs often reflect the values and aspirations of the people who wore or used these gemstones.
Blue Zircon
- Symbolism: Joy, emotional balance, and clarity.
- Metaphysical Beliefs: Blue zircon is believed to enhance emotional stability and promote a sense of peace. It is also associated with spiritual awakening and the expansion of consciousness.
Blue Topaz
- Symbolism: Clarity, self-esteem, and learning.
- Metaphysical Beliefs: Blue topaz is thought to stimulate self-confidence and the ability to learn. It is also believed to align the body's energy meridians and aid in meditation.
Tanzanite
- Symbolism: Spiritual communication, calmness, and protection.
- Metaphysical Beliefs: Tanzanite is considered a stone of transformation and spiritual growth. It is believed to help individuals express their inner truth and connect with higher spiritual realms.
Lapis Lazuli
- Symbolism: Wisdom, truth, and enlightenment.
- Metaphysical Beliefs: Lapis lazuli has been revered for its ability to enhance intellectual clarity and promote a sense of inner peace. It is also believed to stimulate creativity and artistic expression.
Turquoise
- Symbolism: Protection, good fortune, and calmness.
- Metaphysical Beliefs: Turquoise is one of the most widely recognized protective stones. It is believed to bring positive energy, calm the mind, and foster a sense of well-being. In many cultures, it is also associated with communication and emotional healing.
These symbolic and metaphysical beliefs contribute to the enduring popularity of December birthstones and their use in both personal and ceremonial contexts.
Care and Cleaning of December Birthstones
Proper care and cleaning are essential to maintaining the beauty and longevity of December birthstone jewelry. Each gemstone has different requirements based on its hardness, chemical composition, and sensitivity to light and heat.
Blue Zircon
- Hardness: 6–7.5
- Care Instructions: Avoid exposure to harsh chemicals and high temperatures. Clean with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, as they may damage the gemstone's structure.
Blue Topaz
- Hardness: 8
- Care Instructions: Blue topaz is relatively durable and can be cleaned with ultrasonic or steam cleaners. Avoid exposure to prolonged sunlight, as it may cause the color to fade.
Tanzanite
- Hardness: 6–7
- Care Instructions: Tanzanite is sensitive to heat and light. Avoid exposure to direct sunlight for extended periods. Clean with warm, soapy water and a soft cloth. Avoid harsh chemicals and abrasive materials.
Lapis Lazuli
- Hardness: 5–6
- Care Instructions: Lapis lazuli is a soft and porous stone. Avoid exposure to harsh chemicals and abrasive materials. Clean with a soft cloth and mild soap. Avoid ultrasonic cleaners, as they may damage the stone.
Turquoise
- Hardness: 5–6
- Care Instructions: Turquoise is sensitive to water and chemicals. Avoid prolonged exposure to water and store it in a dry place. Clean with a soft cloth and mild soap. Avoid using ultrasonic cleaners or steam cleaners, as they may damage the stone.
By following these care instructions, December birthstone jewelry can remain beautiful and durable for generations.
Conclusion
December's birthstones—blue zircon, blue topaz, tanzanite, lapis lazuli, and turquoise—offer a rich tapestry of color, history, and meaning. Each gemstone brings its own unique properties, from the brilliant fire of zircon to the serene calm of turquoise. These stones have been cherished for centuries, not only for their aesthetic appeal but also for their symbolic and metaphysical significance.
Understanding the geological origins, cultural associations, and care requirements of these gemstones allows for a deeper appreciation of their value and beauty. Whether worn as jewelry, used in meditation, or collected as a hobby, December birthstones continue to captivate and inspire those who encounter them.