Onyx, TOPAZ, and Sard are all kinds of quartz. ONYX is a type of quartz that is usually black or dark gray in color with white or lighter colored veins running through it. TOPAZ is a yellow-orange to brownish-yellow quartz that can also be found in other colors such as pink, blue, and green. Sard is a reddish-brown quartz that is often used in jewelry. All three of these types of quartz are popular for their beauty and durability.