December is a month of cold weather, holiday cheer, and a unique birthstone tradition that sets it apart from the rest of the calendar. Instead of one gemstone, those born in December are blessed with three birthstones: tanzanite, turquoise, and zircon. These three gemstones, all sharing a cool blue palette, symbolize wisdom, protection, and spiritual growth. Though each has its own distinct geological, historical, and cultural background, together they form a cohesive trio that represents the depth and diversity of gemology.
In this article, we explore the unique characteristics of each of these December birthstones. We’ll examine their geological formation, physical properties, historical and cultural significance, and their metaphysical attributes. We’ll also discuss their symbolism, rarity, and care tips to help you make the most of your December birthstone jewelry or collection.
History and Lore
Tanzanite: The Modern Discovery
Tanzanite is the youngest of the three December birthstones, having been discovered in 1967 in Tanzania. Named after its country of origin, tanzanite is a variety of the mineral zoisite. It was not officially recognized as a birthstone until 2002, when it was added to the list of December birthstones by the American National Association of Jewelers.
What makes tanzanite unique is its trichroism—the ability to display three different colors (blue, purple, and red) depending on the angle of light and the viewer’s perspective. This phenomenon, combined with its rarity—since it is only found in a small area near Mount Kilimanjaro—makes tanzanite one of the most sought-after gemstones in the world.
Its relatively recent discovery and limited availability have contributed to its mystique. Tanzanite is often associated with compassion, peace, and harmony, and is said to bring a sense of heightened perception and positive energy to its wearer. Some sources suggest it is also linked to majesty and luck, though these claims are more aligned with modern gemstone lore than historical records.
Turquoise: The Ancient Gem
In stark contrast to tanzanite, turquoise is one of the oldest known gemstones, with a history that dates back thousands of years. It has been treasured by ancient civilizations including the Egyptians, Persians, Chinese, and Native Americans.
Turquoise has a distinctive blue to green-blue color, often adorned with matrix veins—natural patterns formed by the surrounding rock. The name "turquoise" comes from the French phrase "pierre turquoise", meaning "Turkish stone", as the gem was originally brought to Europe via Turkey.
Historically, turquoise was considered a protective stone, especially in the 13th century, when it was believed to shield the wearer from harm and even shatter when danger approached. In Hindu tradition, it was thought that seeing turquoise after the new moon brought wealth. It was also used in burial masks of Egyptian pharaohs and adorned the jewelry of Chinese emperors.
Astrologically, turquoise is associated with the zodiac signs Sagittarius and Pisces, and is believed to enhance wisdom, creativity, and spirituality. It is also thought to promote balance and harmony, making it a popular choice for those seeking emotional and spiritual stability.
Zircon: A Gem of the Ages
Zircon is a geological marvel, with some crystals dating back over 4 billion years. It is one of the oldest minerals on Earth, and in its natural state, it can occur in a rainbow of colors, including red, orange, yellow, green, blue, brown, and colorless. The blue variety, especially, is the most popular and is the one traditionally associated with December.
Zircon has a long and fascinating history. It was used in Victorian-era mourning jewelry, and white zircons were even sold as diamond substitutes as early as the 1300s. The gem is also mentioned in the Bible, referred to as hyacinth or jacinth, and is known to display chatoyance—a cats-eye effect—in certain cuts.
Zircon is highly refractive, and one of the few gemstones to display fire, or rainbow-colored light dispersion. This makes it a popular choice for vintage and estate jewelry, especially for those who appreciate brilliance and clarity without the price tag of diamonds.
Unlike tanzanite, zircon has a more widespread source, with gem-quality stones coming from Sri Lanka, Vietnam, Cambodia, and Myanmar. It is also rarely radioactive, despite containing traces of uranium, and is considered safe for jewelry use.
Geological Formation and Sources
Tanzanite: A Unique Geological Phenomenon
Tanzanite forms from zoisite, a calcium aluminum silicate. Its blue to violet color is the result of trivalent iron impurities within the mineral structure. The gem is only found in a small area near the Mererani Hills in Tanzania, a region known for its tectonic and metamorphic activity.
Geologists estimate that tanzanite formed 585 million years ago, under high pressure and heat caused by tectonic shifts. This extremely limited source—approximately four square miles—makes tanzanite one of the rarest gemstones in the world. Its limited availability has also contributed to its high market value, especially for the deep blue and violet-blue varieties.
Turquoise: A Product of Copper and Time
Turquoise is a secondary mineral that forms when copper-rich water alters phosphorus- and aluminum-bearing minerals. This process usually occurs in arid regions, where evaporation and chemical reactions lead to the precipitation of turquoise.
The most significant sources of turquoise are China and the United States, particularly Nevada and New Mexico. These regions are known for producing high-quality turquoise with strong blue tones and distinct matrix patterns. The matrix, or the veins of surrounding rock, is a natural feature of turquoise and is often considered part of its aesthetic appeal.
Turquoise is opaque, with a refractive index between 1.61 and 1.65. It has a relatively low hardness (5–6 on the Mohs scale), which means it is susceptible to scratches and damage if not handled carefully.
Zircon: The Ancient Crystal
Zircon is a zirconium silicate that is highly resistant to weathering and geological change, which is why some zircon crystals are among the oldest minerals on Earth. It forms in igneous and metamorphic rocks, often containing traces of radioactive elements like uranium and thorium.
This radioactivity is not a concern for jewelry use, but it aids scientists in dating geological events. Zircon's hardness (7.5 on the Mohs scale) makes it more durable than tanzanite and turquoise, and it is often heat-treated to enhance its color—especially the blue zircon associated with December.
Zircon is widespread, with gem-quality stones coming from Sri Lanka, Vietnam, Cambodia, and Myanmar. It is also found in Australia, Brazil, and parts of Africa, making it more accessible than tanzanite, though still relatively rare in the finest blue coloration.
Gemological Properties
Below is a comparison table summarizing the physical and optical properties of the three December birthstones:
| Property | Tanzanite | Turquoise | Zircon |
|---|---|---|---|
| Chemical Formula | Ca₂Al₃(SiO₄)₃(OH) | Hydrated copper aluminum phosphate | ZrSiO₄ |
| Color | Blue to violet-blue, purple | Blue to green-blue | Blue (most popular for Dec), colorless, red, yellow, green |
| Hardness (Mohs) | 6–7 | 5–6 | 7.5 |
| Transparency | Transparent to translucent | Opaque | Transparent to translucent |
| Refractive Index | 1.691–1.700 | 1.61–1.65 | 1.925–1.984 |
| Crystal System | Orthorhombic | Triclinic | Tetragonal |
| Specific Gravity | 3.35 | 2.6–2.8 | 3.90–4.73 |
| Special Properties | Trichroism | Matrix patterns | Dispersion (fire), chatoyance |
This table highlights the unique characteristics of each gemstone. Tanzanite, for instance, is prized for its trichroism, while turquoise is valued for its matrix patterns. Zircon, with its high refractive index and fire, is one of the few gemstones that rival diamonds in brilliance.
Symbolism and Metaphysical Beliefs
Tanzanite: A Stone of Transformation
Tanzanite is often associated with emotional healing and transformation. It is believed to open the third eye and throat chakras, promoting spiritual awareness and communication. In modern gemstone therapy, tanzanite is used to alleviate stress, anxiety, and grief, making it a popular choice for those undergoing emotional or spiritual changes.
Its trichroic nature is also seen as a symbol of seeing the world from multiple perspectives, encouraging empathy and understanding. Some believe it can enhance intuition and perception, making it a favored gemstone for artists, healers, and spiritual seekers.
Turquoise: A Stone of Protection
Turquoise has a long history of use in protective and healing practices. It is believed to ward off negative energy, illness, and misfortune, and is often worn as a charming talisman. In Native American culture, turquoise is considered a stone of power and protection, often used in ceremonial jewelry and amulets.
Its blue and green hues are associated with healing, calmness, and emotional balance, making it a popular stone for meditation and emotional healing. Some traditions also use turquoise to enhance communication and self-expression, making it a versatile gemstone for both personal and spiritual growth.
Zircon: A Stone of Clarity and Energy
Zircon is associated with clarity of thought, energy, and spiritual growth. It is believed to enhance concentration and mental clarity, making it a favored stone for students and professionals. In vintage and estate jewelry, it is also seen as a symbol of love, purity, and eternal life.
Zircon's high refractive index and fire are sometimes interpreted as a symbol of inner brilliance and potential, and the stone is often used in rituals to awaken higher consciousness. Its ancient origins also give it a mystical aura, with some believing it can connect the wearer to ancient wisdom and cosmic energy.
Care and Cleaning
Tanzanite
- Hardness: 6–7
- Durability: Moderate
- Cleaning: Use mild soap and warm water. Avoid ultrasonic or steam cleaning.
- Storage: Store separately from harder gemstones to avoid scratches.
- Avoid: Exposure to direct sunlight and heat, which can cause fading.
Turquoise
- Hardness: 5–6
- Durability: Low
- Cleaning: Use a soft cloth and mild soap. Avoid ultrasonic cleaners and exposure to oils or lotions.
- Storage: Store in a dry place to prevent drying and cracking.
- Avoid: Excessive heat or chemicals, as they can damage the stone or alter its color.
Zircon
- Hardness: 7.5
- Durability: High
- Cleaning: Can be cleaned with mild soap and water or professional ultrasonic cleaning.
- Storage: Store in a dry, secure place.
- Avoid: Exposure to strong chemicals, which can affect the stone's surface or color.
Proper care and handling are essential to maintain the beauty and value of your December birthstone jewelry. Understanding the specific needs of each gemstone can help you extend its life and preserve its luster for generations.
Conclusion
December’s birthstones—tanzanite, turquoise, and zircon—offer a rich tapestry of geological wonder, historical significance, and cultural symbolism. From the trichroic brilliance of tanzanite, to the ancient wisdom of turquoise, and the cosmic clarity of zircon, each gemstone tells its own story.
Whether you’re drawn to the rare and modern appeal of tanzanite, the timeless charm of turquoise, or the brilliant fire of zircon, these gemstones are more than just beautiful—they are windows into the history of the Earth and the spirit of those who wear them.
As December birthstone enthusiasts, collectors, and jewelry lovers, you now have a comprehensive understanding of the blue triad and the unique qualities that make each of these gems so special. Whether for personal enjoyment, spiritual connection, or investment, these December birthstones offer beauty, rarity, and meaning in equal measure.