The marble vs onyx debate is one that has been going on for centuries. Both rocks look similar but have different characteristics. Let's see what each stone is and what's the difference between them.
What is marble?
Marble is a sedimentary rock formed over time by weight and pressure. Marble is usually composed of calcite or dolomite and comes in a variety of colors, including white, black, yellow-gray, gray-brown, green-blue, blue-violet. It is often used in architectural and artistic works.
What is Onyx?
Onyx is a metamorphic rock that forms when parallel bands of quartz crystals are deposited at high temperatures, usually in air pockets in lava flows. Onyx is mostly streaked and predictably wavy, ranging from brown, red and orange to white.
Marble and Onyx: Similarities
Marble and onyx do have some similarities. Marble has the same mineral composition as onyx; both are composed of quartz and various mica minerals such as muscovite, sericite or phlogopite. Both stones have similar colored patterns in the rock, depending on the type.
Marble and Onyx: Differences
Marble and onyx are very similar, but they have some distinct differences. Marble is a metamorphic rock, while onyx is a form of chalcedony quartzite. Marble often appears to be composed of many smaller stones, while onyx surfaces can be dotted with white lines or inclusions.
The most striking difference between the two stones, however, is their color pattern: marble patterns appear as veins and swirls, while onyx's stripes are usually straight or wavy, but not veined.
Marble needs to be polished to get a mirror-like finish. Agate shines on its own without artificial polishing. Both gemstones can take on different color variations, including gray, white, and black. Both may or may not have lines, depending on the species. Both types are mainly used in modern buildings.
