Black onyx has long been prized for its striking appearance and perceived protective qualities. Traditionally recognized as a December birthstone, alongside blue topaz, turquoise, blue zircon, and tanzanite, it offers a sophisticated alternative for those born in the final month of the year. This article delves into the history, geological origins, gemological properties, and care of black onyx, exploring its enduring appeal as a gemstone and birthstone.
History and Lore
The history of onyx is deeply rooted in ancient mythology and belief. The name “onyx” itself originates from the Greek word meaning “fingernail,” a reference to a legend surrounding the stone’s creation. According to this tale, the goddess Venus was sleeping on the banks of the Indus River when her son, Cupid, clipped her fingernails. These clippings fell into the river and, due to their divine origin, transformed into onyx stones, preventing them from vanishing.
Throughout history, onyx has been highly valued. Romans not only inlaid onyx into their seals but also believed it possessed protective powers for soldiers. This belief in its protective capabilities stems from ancient lore where onyx was revered for its ability to ward off evil spirits and provide strength in challenging situations. The psychological impact of wearing onyx was thought to instill confidence and resilience. Beyond its use as a protective amulet, onyx has also been associated with significant life events, serving as a traditional gift for 7th and 10th wedding anniversaries, symbolizing the strength and endurance of a lasting marital bond.
Geological Formation and Sources
Black onyx is a variety of chalcedony, a microcrystalline form of quartz. It belongs to the trigonal crystal system and is formed through silica-rich solutions that deposit within volcanic lava flows. The intensely dark color of black onyx is often achieved through artificial treatment, as naturally occurring black onyx is relatively rare. A common method involves soaking chalcedony in a sugar solution combined with hydrochloric and sulfuric acid, inducing a lustrous black coloration.
While the sources are not specific regarding primary mining locations, the historical prevalence of onyx suggests it has been found in various regions globally. The abundance of black onyx today is, in part, due to these artificial treatment processes, making it readily available in the market.
Gemological Properties
Black onyx exhibits several distinct gemological properties that contribute to its unique characteristics. Its hardness ranges from 6 to 7 on the Mohs scale, indicating moderate durability, requiring careful handling to avoid scratches and damage. The gemstone possesses a vitreous luster, often described as glass-like, with a refractive index of 2.58-2.64.
Typically, black onyx is opaque, meaning light cannot pass through it. Clarity is generally high, with minimal impurities, though it’s advisable to choose stones with smooth surfaces and minimal cracks or inclusions when purchasing jewelry. Black onyx is commonly measured in carats, with carat weight having a less dramatic effect on price compared to some other gemstones; the size of the stone is the primary determinant of its weight.
Black onyx is frequently cut into smooth, glossy cabochons to maximize its luster. However, it can also be faceted into various shapes, including round, oval, trillion, cushion, pear, asscher, and heart cuts. The choice of cut often aims to enhance the stone’s luster and showcase its color and clarity. Well-proportioned stones, even of the same size, can appear more visually appealing due to the quality of their measurements and facet arrangement. The polish of the stone is also crucial; a high-quality polish ensures smooth, even surfaces without roughness or remnants of the rough material.
Symbolism and Metaphysical Beliefs
Throughout history, black onyx has been associated with a range of symbolic meanings and metaphysical beliefs. Its primary association is with protection, guarding the wearer against negativity and providing strength in difficult times. This belief is deeply rooted in ancient traditions and continues to resonate with many today. The stone is also linked to grounding and centering, promoting stability and self-control.
The color black itself often symbolizes power, sophistication, and mystery, further enhancing the allure of black onyx. As a December birthstone, it is believed to offer those born in this month a sense of resilience and inner strength.
Care and Cleaning
Black onyx jewelry is relatively easy to maintain due to its hardness and durability. However, proper care is essential to preserve its luster and prevent damage. It is advisable to avoid contact with makeup, harsh chemicals, and abrasive materials.
Cleaning can be performed using lukewarm water and a mild cleaning detergent. A soft toothbrush can be used to gently clean the underside of the gemstone. To prevent scratches, it is recommended to store onyx jewelry individually, away from other pieces. While black onyx can withstand regular wear with proper care, it’s important to be mindful of potential impacts and abrasions.
Certification
For those seeking assurance of authenticity and quality, black onyx can be certified by reputable gemological laboratories such as the Gemological Institute of America (GIA), the International Gem Society (IGS), and the HRD Antwerp. These certifications provide a detailed report outlining the gemstone’s characteristics, including its color, clarity, cut, and any treatments applied.
Conclusion
Black onyx remains a captivating gemstone, steeped in history and symbolism. Its striking black color, combined with its perceived protective qualities, has made it a cherished adornment for centuries. As a December birthstone, it offers a dramatic and sophisticated alternative to other blue-toned options. Understanding its geological origins, gemological properties, and proper care ensures that this timeless gemstone can be enjoyed for generations to come.