Onyx, with its deep, resonant black coloration and storied past, holds a unique position in the world of birthstones. While it is not the official modern birthstone for December, its historical significance and enduring popularity make it a gemstone worthy of detailed exploration. As a member of the chalcedony family, onyx is prized for its durability and striking appearance, often used in carvings, intaglios, and fine jewelry. This article will delve into the history, geological origins, gemological properties, symbolism, and care of onyx, with a specific focus on its association with the month of December. We will examine its journey from ancient talismans to contemporary jewelry, clarify its status relative to the official December gems, and provide a comprehensive guide for enthusiasts and collectors.
History and Lore
The history of onyx stretches back millennia, with archaeological evidence pointing to its use in ancient civilizations. Although the provided sources do not offer specific details on early uses, they note that its durability and aesthetic appeal likely contributed to its popularity in ancient jewelry and carvings. The tradition of assigning gemstones to specific months gained prominence in 1912 with the standardization efforts of the National Association of Jewelers, though the practice itself has older roots. In this historical context, onyx has been recognized as a traditional birthstone for December.
The sources present a nuanced view of onyx's relationship with December. One source states that onyx is the birthstone for December in the old Tibetan calendar and is also the zodiac stone for Capricorn (December 22–January 20), serving as a talismanic stone for that sign. Another source adds that onyx is associated with the zodiac signs of Leo and is the mystical birthstone for the month of December. Furthermore, onyx is identified as the anniversary gemstone for the 7th year of marriage.
However, a critical evaluation of the sources reveals a significant discrepancy regarding onyx's official status. Multiple sources explicitly state that the three official modern birthstones for December are turquoise, zircon, and tanzanite. One source clarifies that while black onyx is sometimes used in December birthstone jewelry—often as an accent stone, a masculine alternative, or in vintage pieces—it is not considered a traditional or modern December birthstone. It is important to note that the sources do not specify which standardization body (e.g., the American Gem Society or the Jewelry Industry Council of America) designates these official stones, but the consensus among the provided materials is clear: onyx is not among the trio of modern December gems.
Geological Formation and Sources
Onyx is a banded variety of chalcedony, a mineral in the quartz family. The sources describe it as a banded chalcedony of black and white, though black is the most popular color for the December stone. Its formation process involves the deposition of silica in cavities within volcanic rock, creating distinct parallel bands. The classic black onyx is typically composed of alternating layers of black and white silica, though solid black varieties also exist. The sources do not provide specific geographic locations for onyx mining, focusing instead on its gemological and symbolic properties. For comprehensive geological data, one would need to consult additional authoritative sources beyond the provided materials.
Gemological Properties
Onyx possesses a set of distinct physical and optical properties that define its character and value. As a member of the chalcedony family, it shares many characteristics with other quartz varieties but is distinguished by its banding. The following table summarizes key gemological properties of onyx as derived from the provided sources.
| Property | Description |
|---|---|
| Mineral Family | Chalcedony (a microcrystalline variety of quartz) |
| Chemical Composition | Silicon dioxide (SiO₂) |
| Crystal System | Trigonal |
| Hardness (Mohs Scale) | 6.5 to 7 (Note: The source mentions onyx can scratch or chip easily, indicating it requires careful handling despite its moderate hardness.) |
| Luster | Vitreous to waxy |
| Transparency | Opaque to translucent |
| Color | Black (most common for December association), banded black and white. Sardonyx is a reddish-brown variety. |
| Specific Gravity | 2.55–2.70 (Typical for chalcedony; not explicitly stated in sources but standard for the mineral.) |
| Refractive Index | 1.53–1.54 (Typical for chalcedony; not explicitly stated in sources but standard for the mineral.) |
The sources note that onyx may scratch or chip easily, requiring extra care when handling. This characteristic underscores the importance of proper care and setting, especially for jewelry intended for daily wear. The hardness of 6.5 to 7, while respectable, is lower than that of harder gems like sapphire (9) or diamond (10), making it susceptible to abrasion from contact with harder materials.
Symbolism and Metaphysical Beliefs
Onyx is rich in symbolic meaning and is attributed with a wide range of metaphysical properties across various cultures. The sources provide a detailed list of these beliefs, which span physical healing, emotional well-being, and spiritual growth.
Physical and Emotional Healing: Onyx is believed to be a healing stone for ailments of the kidneys and heart. It is also thought to help in the growth of skin, fingernails, and hair. Emotionally, black onyx is considered a grounding stone that can change a wearer's bad habits, reduce neurological disorders, and alleviate stress. It is believed to promote a good night's sleep and help pacify over-eagerness in love.
Spiritual and Mental Benefits: Spiritually, onyx is said to be capable of getting rid of negative thoughts, sharpening the wits, and providing spiritual inspiration. It is also believed to make the wearer eloquent. As a talisman, it has been used historically to provide protection. In ancient times, Romans wore engraved sardonyx gems with images of heroes and gods of war, such as Mars or Hercules/Ares, to render them fearless and brave in battle. This practice highlights onyx's long-standing association with courage and strength.
Zodiac and Calendar Associations: As previously mentioned, onyx is linked to the zodiac signs of Leo and Capricorn. Its association with Capricorn ties it directly to the December-born, particularly in the context of the old Tibetan calendar and as a talismanic stone for the sign. While not a modern official birthstone, its mystical and zodiacal connections firmly place it within the December sphere of influence.
Care and Cleaning
Proper care is essential to maintain the beauty and integrity of onyx jewelry. Given its Mohs hardness of 6.5 to 7 and its tendency to scratch or chip, protective settings are recommended for rings and bracelets that may experience impact. The sources provide specific instructions for cleaning onyx: it can be cleaned using mild soap and lukewarm water. After rinsing the gem properly with water, it should be dried in open air. It is advisable to avoid harsh chemicals, ultrasonic cleaners, and steam cleaners, as these can damage the stone or its setting. Storing onyx jewelry separately from other gems and metals can prevent scratches.
Onyx in the Context of December's Birthstones
To fully understand onyx's place, it is crucial to contextualize it within the broader spectrum of December's birthstones. The modern official birthstones for December are turquoise, zircon, and tanzanite. Turquoise, an opaque blue-green hydrous phosphate containing copper and aluminum, has been mined for over 6,000 years, with ancient Persian and Egyptian origins. It is culturally significant among Native American tribes in the Southwestern United States. Zircon, available in various colors but specifically blue for December, and tanzanite, a newer discovery known for its vibrant blue-to-violet hues, complete the trio.
The color blue is overwhelmingly associated with December in modern gemology. One source states, "The birthstone color for December is undoubtedly blue," noting that while non-conventional stones like ruby (red) and onyx (black) add other colors, blue remains the widely accepted hue. Onyx, with its classic black color, offers a dramatic contrast to these blue gems. Its use in December jewelry often serves as an accent to highlight the blue stones or as a masculine alternative due to its darker, more subdued aesthetic.
Conclusion
Onyx is a gemstone of profound historical depth and symbolic power. While it is not officially recognized as a modern birthstone for December, its traditional association with the month, particularly through its zodiacal link to Capricorn and its status in the old Tibetan calendar, secures its relevance. As a durable chalcedony with a striking black color, it has been cherished for millennia for both ornamental and talismanic purposes. Its metaphysical properties—spanning physical healing, emotional grounding, and spiritual inspiration—add layers of meaning that continue to resonate with wearers today. For those born in December, onyx represents a connection to ancient traditions and a powerful, protective talisman, even as they may choose the official blue gems of turquoise, zircon, or tanzanite for their birthday celebrations. Proper care, mindful of its moderate hardness, will ensure that this timeless stone endures as a cherished piece of jewelry and a symbol of strength and protection.