December is a month of cold weather, holiday cheer, and a unique distinction in the world of gemstones: it is the only month with four officially recognized birthstones. These include Tanzanite, Turquoise, Blue Zircon, and Blue Topaz. Each of these gemstones carries its own rich history, distinct gemological properties, and symbolic meaning, making them ideal choices for jewelry and personal adornment. This article provides an in-depth exploration of these four December birthstones, drawing from historical, geological, and cultural sources to present a comprehensive overview.
Introduction
The tradition of associating gemstones with specific months is a practice with ancient roots, believed to have originated in Mesopotamia and later adopted by the ancient Greeks and Romans. The December birthstones, in particular, have undergone several changes over time. Originally, only Turquoise and Zircon were considered December’s gemstones. However, in the 20th century, the list expanded to include Blue Topaz and Tanzanite, the latter being the most recent addition in 2002. This expansion reflects not only the evolving nature of the birthstone tradition but also the growing appreciation for new gemstone discoveries and their commercial appeal.
December’s birthstones are all characterized by their blue hues, a nod to the cool tones of winter and the calmness associated with the season. Each gemstone, while sharing this common color theme, has its own unique story, properties, and cultural significance. The following sections will explore these four gemstones in detail, covering their origins, gemological characteristics, symbolism, and care instructions.
History and Lore
Turquoise: The Ancient December Birthstone
Turquoise is the oldest and most traditional of December’s birthstones. Its use dates back thousands of years, with evidence of its presence in ancient Egyptian, Persian, and Native American cultures. It was highly prized by royalty, including King Tutankhamun, whose tomb contained turquoise-adorned jewelry and artifacts.
Turquoise was believed to offer protection, good health, and good luck. In many cultures, it was used in amulets and talismans to ward off negative energies and to promote wisdom and tranquility. The gemstone was also thought to have the power to enhance communication and foster friendship.
The most prized variety of turquoise, known as Persian turquoise, comes from ancient mines in Iran. It is celebrated for its vivid sky-blue color and minimal matrix (the dark veins that appear in many turquoise stones). Another highly valued type is Sleeping Beauty Turquoise, which was mined exclusively from the Sleeping Beauty Mine in Arizona before its closure. It is known for its pure, robin’s-egg blue color and smooth, uniform appearance.
Zircon: A Sparkling Blue Classic
Zircon, in its blue form, has also been a part of the December birthstone tradition for centuries. It is one of the oldest minerals on Earth, with zircon crystals found in geological formations dating back over 4.4 billion years. Zircon’s name comes from the Arabic word zarkun, meaning “gold-like,” a reference to the yellowish or reddish tones of some zircon varieties.
Blue zircon was historically valued for its brilliance and fire, making it a popular alternative to diamonds in jewelry. It was used in ancient cultures and has been rediscovered in modern times as a durable and affordable gemstone. The blue color is achieved through heat treatment, which transforms the gem from a brown or yellow hue into a vibrant blue.
Zircon’s inclusion in December’s birthstone list was formalized in 1952 by the Jewelry Industry Council of America, adding it to the traditional December stones of Turquoise and Tanzanite.
Blue Topaz: A Modern Addition
Blue Topaz became a recognized December birthstone in the 20th century, and it has since gained popularity as a durable and affordable option for jewelry. Unlike natural blue topaz, which is rare, the blue color in most blue topaz gemstones is achieved through irradiation and heat treatment. This process transforms the gem into the deep blue or sky-blue hues that are so desirable in jewelry.
Blue topaz is the hardest of the four December birthstones, with a Mohs hardness of 8, making it suitable for everyday wear. It was officially recognized as a December birthstone in 1998, and its inclusion reflects the growing trend of using more durable and versatile gemstones in jewelry design.
Tanzanite: The Rarest of the Four
Tanzanite, the most recent addition to the December birthstone list, was discovered in 1967 in Tanzania, from which it takes its name. It was officially recognized as a December birthstone in 2002. Tanzanite is known for its vivid blue to violet-blue color, which is caused by trace amounts of vanadium in its crystal structure.
What sets tanzanite apart is its rarity—it is only found in a small region of Tanzania, making it one of the most exclusive gemstones in the world. It has a trigonal crystal structure and a Mohs hardness of 6 to 7, which means it requires careful handling to avoid scratches and damage. Tanzanite is also trichroic, meaning it can display three different colors when viewed from different angles—blue, violet, and brown.
Tanzanite quickly became a favorite among jewelers and collectors due to its vibrant color and affordability. It has since become a symbol of luxury and exclusivity, often used in fine jewelry and as a center stone in engagement rings and pendants.
Geological Formation and Sources
Formation and Sources of Turquoise
Turquoise forms in the oxidation zones of copper deposits, where water percolates through the rock and carries dissolved minerals that precipitate to form the gemstone. It is typically found in arid regions, where the dry climate helps preserve the turquoise from weathering and erosion.
Significant sources of turquoise include:
- Iran (Persian Turquoise)
- United States (Sleeping Beauty Mine in Arizona, Nevada, New Mexico)
- China
- Egypt
- Mexico
- Central Asia and Africa
Turquoise is often found with matrix, which refers to the dark mineral veins that run through the stone. The amount and pattern of matrix can affect the stone’s value and appearance. Persian turquoise is especially prized for its minimal matrix and even color distribution.
Formation and Sources of Zircon
Zircon is a silicate mineral that forms in igneous rocks, such as granite, and is commonly found in metamorphic and sedimentary rocks. It is one of the oldest known minerals on Earth, with some zircon crystals dating back over 4.4 billion years.
Blue zircon is created through a heat treatment process that transforms the natural brown or yellow zircon into a vibrant blue color. This treatment is stable and widely accepted in the gemstone industry.
Zircon is mined in various parts of the world, including:
- Australia
- Brazil
- India
- Madagascar
- Zimbabwe
Formation and Sources of Blue Topaz
Blue topaz is a silicate mineral that forms in granitic rocks and pegmatites, where it can grow into large, well-formed crystals. Natural blue topaz is extremely rare, so most blue topaz in the market is produced through irradiation and heat treatment to enhance its color.
Natural topaz forms in a variety of colors, including colorless, yellow, brown, and pink. The blue color is achieved by irradiating the stone and then heating it, a process that is both safe and stable.
Major sources of topaz include:
- Brazil
- Mexico
- Nigeria
- Sri Lanka
- United States
Blue topaz is the hardest of the four December birthstones, with a Mohs hardness of 8, making it ideal for everyday jewelry use.
Formation and Sources of Tanzanite
Tanzanite is a trigonal mineral that forms in metamorphic rocks, specifically in the transition zones where the rock is undergoing high pressure and temperature. It was first discovered in 1967 in Tanzania, in the Merelani Hills near the city of Arusha.
Tanzanite is unique because it is only found in one location in the world, making it one of the rarest gemstones. The gemstone's color is due to traces of vanadium, which cause the trichroism—the ability to display three different colors depending on the angle of view.
Tanzanite is trigonal in crystal structure and has a Mohs hardness of 6 to 7, which is moderate for a gemstone. It is vulnerable to scratches and abrasions, so it requires careful handling and cleaning.
The limited availability of tanzanite and its vibrant color have made it a highly sought-after gemstone in the jewelry industry.
Gemological Properties
| Gemstone | Color | Hardness (Mohs Scale) | Chemical Formula | Specific Gravity | Refractive Index | Origin of Blue Color |
|---|---|---|---|---|---|---|
| Turquoise | Blue to greenish-blue | 5–6 | CuAl₆(PO₄)₄(OH)₈·4H₂O | 2.7 to 2.9 | 1.61 to 1.65 | Natural formation in copper-rich deposits |
| Zircon | Blue (treated) | 6–7.5 | ZrSiO₄ | 4.6 to 4.8 | 1.92 to 2.01 | Heat treatment |
| Blue Topaz | Blue (treated) | 8 | Al₂SiO₆ | 3.5 to 3.6 | 1.61 to 1.63 | Irradiation and heat treatment |
| Tanzanite | Blue to violet-blue | 6–7 | Ca₂Al₃(SiO₄)₃(OH) | 3.1 to 3.4 | 1.694 to 1.701 | Trace vanadium |
Turquoise
- Color: Ranges from sky blue to greenish-blue, with some stones displaying matrix patterns.
- Hardness: 5–6 on the Mohs scale.
- Chemical Formula: CuAl₆(PO₄)₄(OH)₈·4H₂O.
- Specific Gravity: 2.7 to 2.9.
- Refractive Index: 1.61 to 1.65.
- Origin of Blue Color: Natural formation in copper-rich deposits.
Zircon
- Color: Blue (treated), though naturally brown or yellow.
- Hardness: 6–7.5 on the Mohs scale.
- Chemical Formula: ZrSiO₄.
- Specific Gravity: 4.6 to 4.8.
- Refractive Index: 1.92 to 2.01.
- Origin of Blue Color: Achieved through heat treatment.
Blue Topaz
- Color: Blue (treated), with natural topaz being colorless or yellow.
- Hardness: 8 on the Mohs scale.
- Chemical Formula: Al₂SiO₆.
- Specific Gravity: 3.5 to 3.6.
- Refractive Index: 1.61 to 1.63.
- Origin of Blue Color: Irradiation and heat treatment.
Tanzanite
- Color: Blue to violet-blue.
- Hardness: 6–7 on the Mohs scale.
- Chemical Formula: Ca₂Al₃(SiO₄)₃(OH).
- Specific Gravity: 3.1 to 3.4.
- Refractive Index: 1.694 to 1.701.
- Origin of Blue Color: Trace amounts of vanadium in the crystal structure.
Symbolism and Metaphysical Beliefs
Turquoise: A Stone of Protection and Wisdom
Turquoise has long been regarded as a stone of protection, especially in ancient cultures. It was believed to shield the wearer from harm, both physical and spiritual. In many cultures, turquoise was used in amulets and talismans to ward off negative energies and to promote good health and good luck.
In Native American cultures, turquoise is considered a sacred stone, often used in ceremonial jewelry and healing practices. It is associated with healing, balance, and communication.
Modern metaphysical beliefs also assign positive meanings to turquoise. It is said to enhance communication, foster friendship, and promote inner peace. It is often recommended for those who struggle with anxiety or stress, as it is believed to have a calming effect on the mind and body.
Zircon: A Stone of Transformation and Clarity
Zircon is known for its brilliance and fire, which has led to its association with clarity and transformation. In ancient times, zircon was believed to have protective and healing properties, especially when used in amulets and talismans.
Zircon is also associated with spiritual growth and transformation. It is believed to help the wearer clear the mind, gain insight, and understand their true purpose. In some cultures, zircon is used in dream work and meditation, as it is thought to enhance intuition and psychic abilities.
Modern metaphysical beliefs regard zircon as a stone of wisdom and truth. It is often recommended for those who seek clarity and direction in their lives, as it is believed to help the wearer see the big picture and make wise decisions.
Blue Topaz: A Stone of Courage and Communication
Blue topaz is associated with calmness, courage, and communication. It is believed to help the wearer speak their truth, express their emotions, and build strong relationships.
In ancient times, topaz was believed to have protective and healing properties, especially when used in amulets and talismans. It was also thought to enhance courage and strength, making it a popular choice for warriors and leaders.
Modern metaphysical beliefs regard blue topaz as a stone of peace and serenity. It is often recommended for those who struggle with anxiety, fear, or emotional instability, as it is believed to calm the mind, soothe the heart, and promote emotional balance.
Tanzanite: A Stone of Intuition and Emotional Healing
Tanzanite is associated with intuition, emotional healing, and spiritual transformation. It is believed to help the wearer process emotions, release negative feelings, and connect with their inner self.
Tanzanite is also associated with spiritual growth and awakening. It is believed to help the wearer expand their consciousness, gain insight, and understand their true purpose. In some cultures, tanzanite is used in dream work and meditation, as it is thought to enhance psychic abilities and intuition.
Modern metaphysical beliefs regard tanzanite as a stone of transformation and healing. It is often recommended for those who are going through major life changes or emotional upheaval, as it is believed to help the wearer navigate their journey with clarity and grace.
Care and Cleaning
Turquoise
- Cleaning: Gently wipe with a soft, damp cloth to remove dirt and oils. Avoid using ultrasonic cleaners or steamers, as they can damage the stone.
- Storage: Store turquoise away from direct sunlight and heat, as it can cause fading and drying.
- Handling: Handle turquoise with clean hands to avoid oils and lotions that can dull its surface.
Zircon
- Cleaning: Use warm water and mild soap to clean zircon. Avoid ultrasonic cleaners, as they can cause micro-fractures in the stone.
- Storage: Store zircon in a soft pouch or jewelry box to avoid scratches and abrasions.
- Handling: Handle zircon with care, as it can be susceptible to chipping if hit against hard surfaces.
Blue Topaz
- Cleaning: Clean blue topaz with warm water and mild soap. It can also be safely cleaned with an ultrasonic cleaner.
- Storage: Store blue topaz in a soft pouch or jewelry box to avoid scratches and abrasions.
- Handling: Blue topaz is durable enough for everyday wear, but it should still be handled with care to avoid knocking it against hard surfaces.
Tanzanite
- Cleaning: Clean tanzanite with warm water and mild soap. Avoid ultrasonic cleaners, as they can damage the stone’s internal structure.
- Storage: Store tanzanite in a soft pouch or jewelry box to avoid scratches and abrasions.
- Handling: Tanzanite is vulnerable to scratches and abrasions, so it should be handled with care and avoided in rough activities.
Conclusion
December is a month of unique distinction in the world of gemstones, as it is the only month with four officially recognized birthstones: Tanzanite, Turquoise, Blue Zircon, and Blue Topaz. Each of these gemstones has its own rich history, distinct gemological properties, and symbolic meaning, making them ideal choices for jewelry and personal adornment.
Turquoise, the oldest and most traditional of the four, has been cherished for thousands of years for its protective and healing properties. Zircon, with its brilliance and fire, has been a popular choice for centuries and was added to the December birthstone list in 1952. Blue Topaz, the hardest of the four, became a modern addition in the 20th century due to its durability and affordability. Tanzanite, the most recent addition in 2002, is known for its rarity and vibrant color, making it a symbol of luxury and exclusivity.
These gemstones not only offer aesthetic beauty but also carry deep cultural and historical significance, making them a meaningful choice for those born in December. Whether you are a gemstone enthusiast, a jewelry buyer, or a student of gemology, the December birthstones offer a fascinating glimpse into the world of gemstones and their enduring appeal.