Onyx
| Property | Details |
|---|
| Mineral | Chalcedony (quartz family) |
| Mohs Hardness | 6.5 – 7 |
| Refractive Index | 1.530 – 1.539 |
| Major Sources | Brazil, India, Madagascar, Uruguay |
| Treatments | Dyeing to achieve uniform black (standard, permanent) |
Overview
Onyx is a variety of chalcedony most commonly known in its solid black form. Black onyx has been used in jewelry and carvings since antiquity and remains one of the most popular black gemstones for men's jewelry, signet rings, cuff links, and bold fashion pieces. Its opaque, uniformly black surface provides a dramatic backdrop for diamonds and creates striking contrast in two-tone designs.
Varieties
Black onyx: The most recognized form, used extensively in men's and fashion jewelry. Sardonyx: A banded variety combining black onyx with reddish-brown sard, traditionally used for cameo carvings. Most commercial black onyx is dyed to achieve a uniform deep black color, a permanent and long-accepted treatment.
Care & Cleaning
Onyx ranks 6.5 to 7 on the Mohs scale and is durable enough for most jewelry. Clean with warm soapy water and a soft cloth. Avoid harsh chemicals and prolonged soaking.