December boasts a rich and varied selection of birthstones, moving beyond historical associations with ruby and bloodstone to encompass the captivating blues and greens of turquoise, blue zircon, and the more recently discovered tanzanite. While blue is the dominant color theme, each gemstone offers a unique history, geological origin, and symbolic meaning. This article will delve into the characteristics of these December birthstones, exploring their historical significance, geological formation, gemological properties, and cultural associations, as understood through available sources.
History and Lore
The designation of birthstones has evolved over time. Until the 20th century, December was linked to ruby and bloodstone. A shift occurred in 1912 when the United States recognized lapis lazuli and turquoise as December birthstones. Later, in 2013, England officially acknowledged turquoise and tanzanite as representing the month. Currently, the American Gem Trade Association and Jewelers of America identify turquoise, blue zircon, and tanzanite as the primary December birthstones.
Turquoise holds a particularly long and storied history, cherished for millennia across numerous cultures. Ancient Egyptians adorned themselves with turquoise, and Chinese artisans were carving the stone over 3,000 years ago. It was believed to possess protective powers, safeguarding wearers from harm, even preventing falls from horses. Hindu mystics associated turquoise with wealth and good fortune when viewed after a new moon.
Blue zircon, while less steeped in ancient lore than turquoise, has a history as a diamond substitute due to its high refractive index and brilliance. Tanzanite, being a relatively recent discovery in the 1960s, lacks the extensive historical background of its counterparts, but quickly gained prominence after being marketed by Tiffany & Co.
Geological Formation and Sources
The origins of these December birthstones are geographically diverse. Turquoise, characterized by its opaque blue to green hues and often featuring matrix veining, forms in relatively dry, arid environments.
Blue zircon is found in several locations, with primary mining occurring in Thailand, Cambodia, and Vietnam. Interestingly, zircon contains trace amounts of uranium and thorium, making it valuable in radiometric dating, with some specimens calculated to be up to 4.4 billion years old – among the oldest minerals on Earth.
Tanzanite is exceptionally unique, found in a limited geographical area near Mount Kilimanjaro. It is not known to exist anywhere else in the world. Blue topaz is mined in parts of the US, China, Mexico, and Russia.
Gemological Properties
Each of these gemstones possesses distinct gemological properties. Turquoise is a semi-translucent to opaque gem, its color stemming from copper content. The presence of matrix, remnants of the host rock, is a common characteristic.
Blue zircon boasts a very high refractive index, contributing to its brilliance. Natural zircon occurs in a variety of colors, and the blue variety is often achieved through heat treatment.
Tanzanite is a transparent blue crystal, displaying colors ranging from blue to purple, and intensities from pastel to vivid. It exhibits strong pleochroism, meaning it displays different colors when viewed from different angles and under varying lighting conditions. Like blue zircon, tanzanite is commonly heat-treated to enhance its coloration.
Blue topaz, often colorless or faintly colored in its natural state, is frequently treated to achieve a sky-bluish delicate appearance. Variations like London Blue, Swiss Blue, and Sky Blue Topaz are popular choices for jewelry.
The following table summarizes key properties:
| Gemstone | Color(s) | Transparency | Hardness (Mohs) | Notable Properties |
|---|---|---|---|---|
| Turquoise | Blue to Green | Semi-opaque | 5-6 | Often contains matrix; historically protective |
| Blue Zircon | Blue | Transparent | 6.5-7.5 | High refractive index; can be heat-treated |
| Tanzanite | Blue to Purple | Transparent | 6-7 | Pleochroic; typically heat-treated; rare origin |
| Blue Topaz | Various shades of Blue | Transparent | 8 | Often heat-treated to enhance color |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been attributed with various symbolic meanings and metaphysical properties. Turquoise, particularly in India, is considered the birthstone for Sagittarius (November 21 to December 21) and is believed to promote good health and healing. Traditional Hindu practices involve setting birthstones in jewelry to ensure direct skin contact with the stone, maximizing its perceived benefits.
While specific metaphysical beliefs surrounding blue zircon and tanzanite are less detailed in the provided sources, the general association of blue gemstones with tranquility, wisdom, and inspiration is likely applicable. The shift from the red hues of earlier December birthstones (ruby and bloodstone) to the cooler blues and greens reflects a change in symbolic associations, potentially aligning with the winter season and themes of introspection and peace.
Care and Cleaning
The care required for each gemstone varies based on its hardness and other properties. Turquoise, being relatively soft (5-6 on the Mohs scale), is susceptible to scratching and should be handled with care. Avoid harsh chemicals and ultrasonic cleaners. Cleaning can be done with a soft cloth and mild soapy water.
Blue zircon and tanzanite, with hardness ratings of 6.5-7.5 and 6-7 respectively, are more durable but still require careful handling. Avoid sudden temperature changes and harsh chemicals. Cleaning can be performed with warm, soapy water and a soft brush.
Blue topaz, being the hardest of the December birthstones (8 on the Mohs scale), is relatively durable and can withstand more wear and tear. However, it is still advisable to avoid harsh chemicals and ultrasonic cleaners. Cleaning can be done with warm, soapy water and a soft brush.
December 25th Birthstone
According to the provided data, December 25th specifically corresponds to Tanzanite as a birthstone. However, the sources also indicate a rotating pattern of birthstones throughout the month, with Blue Topaz, Turquoise, and Blue Zircon also being associated with various dates in December.
Conclusion
December’s birthstones – turquoise, blue zircon, and tanzanite – represent a captivating spectrum of color, history, and geological origins. From the ancient protective powers attributed to turquoise to the modern allure of tanzanite and the diamond-like brilliance of blue zircon, these gemstones offer a diverse range of options for those born in the final month of the year. The evolution of December’s birthstone designations reflects changing cultural beliefs and the discovery of new and exciting gemstones, solidifying their place as cherished symbols of the season and personal significance.