December, the final month of the calendar year, is rich in symbolism and tradition. It marks the arrival of the winter season, the celebration of major holidays like Christmas and Hanukkah, and the anticipation of the New Year. In the world of gemstones, December is particularly unique, as it is one of the few months with multiple birthstones. These stones—blue topaz, blue zircon, tanzanite, turquoise, and lapis lazuli—each have their own distinct history, properties, and cultural significance. This article explores these December birthstones in depth, delving into their origins, meanings, gemological characteristics, and their roles in both jewelry and metaphysical traditions.
History and Lore
The tradition of associating gemstones with specific months is centuries old, with roots in ancient religious and cultural texts. The earliest known references to birthstones can be traced back to the Book of Exodus in the Bible, where the Breastplate of Aaron is described as containing 12 different gems, each representing one of the 12 tribes of Israel. Over time, these stones were linked to the months of the year, forming the basis of the modern birthstone tradition.
For December, the birthstone list has evolved significantly over the centuries. Initially, ruby was listed as the December birthstone in early versions of the birthstone calendar. By the 1870s, turquoise was designated as the official December birthstone by Tiffany & Co. through their Gregorian Birthstone Poems pamphlet. In 1912, the National Association of Jewellers (now the Jewellers of America) included lapis lazuli as an alternative to turquoise.
The 1952 update by the Jewelry Industry Council of America added zircon to the list, and in 2002, tanzanite was officially recognized as a December birthstone. Blue topaz has also become a widely accepted modern alternative, especially due to its widespread availability and affordability.
This evolution reflects both historical preferences and the influence of the jewelry industry in shaping contemporary birthstone lists. The inclusion of multiple stones for December reflects not only the diversity of gemstone options but also the changing tastes and accessibility of certain gems over time.
Geological Formation and Sources
Each December birthstone originates from different geological environments and geographic locations, shaped by the unique conditions that allow them to form.
Turquoise
Turquoise is a phosphate mineral composed of basic aluminum phosphate, with the chemical formula Al₂(P₂O₇)(OH)₃·H₂O. It forms in the oxidized zones of copper deposits, typically in arid climates where water percolates through the rock and reacts with the minerals. Turquoise is known for its vibrant blue to green color, which varies depending on the concentration of copper (blue) and iron (green). It is often found with matrix lines—natural veins of the host rock that run through the stone.
Major sources of turquoise include Nevada (USA), Iran (Persia), China, and Egypt. The Persian turquoise from Iran is particularly famous for its deep blue color with black matrix.
Zircon
Zircon is a zirconium silicate with the chemical formula ZrSiO₄. It is one of the oldest minerals on Earth, with some zircon crystals found to be over 4.4 billion years old. Zircon forms in igneous rocks, especially granite, and can be found in alluvial deposits as well. It is known for its high refractive index, which gives it a brilliant fire and dispersion, similar to diamonds.
Blue zircon, the most popular variety for December, is a treated version of the stone, created through heat treatment that removes any yellow or brown hues and produces a rich blue color. Zircon is found in countries such as Australia, Cambodia, and Brazil.
Tanzanite
Tanzanite is a trigonal mineral and a variety of the zoisite family with the chemical formula Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)₃·H₂O. It is unique to the region of Tanzania, near the base of Mount Kilimanjaro, where it was discovered in 1967 by gemstone miner Manuel de Souza. The stone’s violet-blue color is due to trace amounts of vanadium, which is activated through heat treatment.
Tanzanite is only found in a very limited area, which makes it rare and highly valuable. The gem is known for its trichroism, meaning it can display three different colors (blue, purple, and brown) depending on the viewing angle. Due to its limited source and the increasing depletion of the mine, tanzanite is considered one of the most exclusive birthstones.
Blue Topaz
Blue topaz is a silicate mineral with the chemical formula Al₂SiO₆. It is the blue variety of topaz, a stone known for its hardness and clarity. Naturally occurring blue topaz is rare, and most blue topaz used in jewelry is irradiated and heat-treated to produce the beautiful blue color.
Topaz is found in a variety of igneous and metamorphic rocks, and blue topaz is especially abundant in Brazil, Nigeria, and the United States. The hardness of topaz (8 on the Mohs scale) makes it a durable gemstone suitable for everyday wear.
Lapis Lazuli
Lapis lazuli is a metamorphic rock composed primarily of lazurite, with smaller amounts of pyrite and calcite. It is known for its deep blue color with flecks of golden pyrite, which gives it a striking visual contrast. Lapis lazuli forms under high-pressure, low-temperature conditions, often in calcite-rich marbles.
The most famous source of lapis lazuli is Afghanistan, where it has been mined for thousands of years. Other sources include Russia, Chile, and Argentina. The stone has been used since ancient times, with Egyptian royalty often inlaid with lapis lazuli for jewelry and ceremonial objects.
Gemological Properties
To understand the appeal of December birthstones, it's essential to examine their scientific properties, including hardness, refractive index, color, and clarity.
Turquoise
- Hardness: 5–6 on the Mohs scale
- Refractive Index: 1.61–1.65
- Color: Blue to green, with variations due to impurities
- Clarity: Typically opaque with visible matrix lines
- Luster: Waxy to greasy
- Specific Gravity: 2.6–2.8
Turquoise is relatively soft and porous, which makes it susceptible to damage from oils, chemicals, and abrasion. It is best suited for protective settings and avoided in daily wear unless well-protected.
Zircon
- Hardness: 6.5–7.5 on the Mohs scale
- Refractive Index: 1.92–2.00 (very high)
- Color: Blue, yellow, brown (blue zircon is most popular)
- Clarity: Often included, with visible inclusions
- Luster: Vitreous to subadamantine
- Specific Gravity: 4.6–4.8
Zircon is very brilliant and has a high refractive index, making it an excellent diamond simulant. However, it is cleavage-prone, so it should be set carefully to avoid chipping.
Tanzanite
- Hardness: 6–6.5 on the Mohs scale
- Refractive Index: 1.694–1.701
- Color: Violet-blue (trichroic)
- Clarity: Usually included, with visible inclusions
- Luster: Vitreous
- Specific Gravity: 3.35–3.45
Tanzanite is rare and valuable due to its limited source and unique color. It is soft and sensitive to heat, which is why it is heat-treated to enhance its color and stability.
Blue Topaz
- Hardness: 8 on the Mohs scale
- Refractive Index: 1.61–1.63
- Color: Blue (naturally rare)
- Clarity: Usually eye-clean
- Luster: Vitreous
- Specific Gravity: 3.53–3.57
Blue topaz is a very durable gemstone, making it ideal for everyday wear. It is often irradiated and heat-treated to achieve its blue color, which is stable under normal conditions.
Lapis Lazuli
- Hardness: 5–6 on the Mohs scale
- Refractive Index: 1.6–1.7
- Color: Deep blue with golden flecks
- Clarity: Typically opaque with visible inclusions
- Luster: Waxy to greasy
- Specific Gravity: 2.4–2.9
Lapis lazuli is soft and porous, so it is best suited for protective settings. It is often inlaid or carved, rather than set in standard jewelry settings.
| Gemstone | Hardness | Refractive Index | Color | Clarity | Luster | Specific Gravity |
|---|---|---|---|---|---|---|
| Turquoise | 5–6 | 1.61–1.65 | Blue to green | Opaque | Waxy | 2.6–2.8 |
| Zircon | 6.5–7.5 | 1.92–2.00 | Blue, yellow, brown | Included | Vitreous | 4.6–4.8 |
| Tanzanite | 6–6.5 | 1.694–1.701 | Violet-blue | Included | Vitreous | 3.35–3.45 |
| Blue Topaz | 8 | 1.61–1.63 | Blue | Eye-clean | Vitreous | 3.53–3.57 |
| Lapis Lazuli | 5–6 | 1.6–1.7 | Deep blue with gold | Opaque | Waxy | 2.4–2.9 |
Symbolism and Metaphysical Beliefs
Each of December’s birthstones carries its own spiritual and cultural significance, with many of these beliefs rooted in ancient traditions.
Turquoise
- Symbolism: Protection, healing, and communication.
- Metaphysical Beliefs: Turquoise is often considered a stone of protection and healing. It is believed to enhance communication, promote emotional stability, and aid in spiritual awakening.
- Cultural Significance: Turquoise has been used for centuries by Native American tribes and Persian cultures as a protective amulet and ceremonial stone. It is often referred to as the "stone of the sky."
Zircon
- Symbolism: Clarity, intuition, and grounding.
- Metaphysical Beliefs: Zircon is believed to enhance mental clarity, boost intuition, and provide a sense of grounding. It is also associated with time travel and ancient wisdom, given its millions of years of existence.
- Cultural Significance: Zircon has been used in ancient jewelry and ceremonial objects in Egyptian and Greek cultures, where it was valued for its brilliance and clarity.
Tanzanite
- Symbolism: Transformation, intuition, and emotional balance.
- Metaphysical Beliefs: Tanzanite is considered a stone of transformation and emotional healing. It is believed to open the heart and mind to new possibilities, enhance intuition, and promote emotional balance.
- Cultural Significance: As a modern discovery, tanzanite has quickly become a symbol of exclusivity and rarity, often used in high-end jewelry and ceremonial gifts.
Blue Topaz
- Symbolism: Calmness, communication, and emotional balance.
- Metaphysical Beliefs: Blue topaz is associated with calmness, communication, and emotional balance. It is believed to enhance clarity of thought, promote understanding, and foster peace of mind.
- Cultural Significance: Blue topaz has become a popular modern birthstone due to its affordability and vibrant blue color. It is often used in engagement rings and pendants.
Lapis Lazuli
- Symbolism: Wisdom, truth, and spiritual enlightenment.
- Metaphysical Beliefs: Lapis lazuli is considered a stone of wisdom and truth. It is believed to enhance spiritual awareness, stimulate the mind, and promote honesty and integrity.
- Cultural Significance: Lapis lazuli has been used for thousands of years, particularly in ancient Egypt, where it was associated with royalty and divinity. It was often used in jewelry and ceremonial objects to symbolize power and wisdom.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of December birthstone jewelry. Each gemstone requires specific cleaning and storage techniques due to its unique properties and vulnerabilities.
Turquoise
- Cleaning: Gently clean with a soft cloth and lukewarm water. Avoid using ammonia, alcohol, or harsh detergents.
- Storage: Store in a dry, cool place, away from direct sunlight and other gemstones that might scratch it.
- Avoid: Exposure to oils, lotions, and chemicals, which can damage the porous surface.
Zircon
- Cleaning: Use a mild soap and warm water. Avoid using ultrasonic cleaners, as they can damage inclusions and internal structures.
- Storage: Store in a soft pouch or lined box, away from hard objects that might chip the gemstone.
- Avoid: Exposure to extreme heat, as zircon can crack or fracture under high temperatures.
Tanzanite
- Cleaning: Gently clean with warm water and a mild detergent. Avoid ultrasonic and steam cleaners, as they can damage the inclusions and internal structure.
- Storage: Store in a soft pouch or lined box, away from hard objects.
- Avoid: Exposure to heat, which can alter the color and structure of the gemstone.
Blue Topaz
- Cleaning: Clean with warm water and mild detergent. Ultrasonic and steam cleaners are generally safe for blue topaz.
- Storage: Store in a soft pouch or lined box.
- Avoid: Exposure to abrasive materials, as topaz is very hard but can still be scratched by harder stones.
Lapis Lazuli
- Cleaning: Gently clean with lukewarm water and a soft cloth. Avoid harsh chemicals or abrasive materials.
- Storage: Store in a dry, cool place, away from other gemstones.
- Avoid: Exposure to direct sunlight, which can fade the color over time.
Conclusion
December is a month of transition, celebration, and reflection, and its birthstones reflect these themes with their diverse colors, histories, and meanings. The five December birthstones—turquoise, zircon, tanzanite, blue topaz, and lapis lazuli—each offer unique characteristics and cultural significance, making December one of the most versatile and meaningful months in the birthstone calendar.
From the ancient turquoise used by Persian and Native American cultures to the modern tanzanite discovered in Tanzania in 1967, these gemstones have evolved in both their physical and symbolic meanings. Whether you choose a soft blue topaz for its calming energy, a brilliant zircon for its fire, or a rare tanzanite for its exclusivity, December’s birthstones offer a rich tapestry of choice and meaning.
Understanding the history, properties, and symbolism of these gemstones allows for a deeper appreciation of their role in jewelry, culture, and personal expression. Whether as birthstone jewelry, ceremonial stones, or spiritual tools, these December gems continue to captivate and inspire across generations.