Gemstones & Minerals Is onyx just black quartz? February 6, 2026 by Myaya | Leave a Comment Onyx and black quartz are often confused due to their similar appearance, but they are distinct minerals with different compositions and characteristics. Onyx is a type of chalcedony, a form of silica, while black quartz is a variety of quartz, both of which are valued in jewelry and decorative arts. What Is Onyx? Onyx is […] Read more ยป