Onyx marble belongs to the comparatively small mineral group of carbonates or limestones . Within this group, the onyx marble is a representative of the calc sinter, also known as spring lime or freshwater lime. This includes all the minerals that are secondary, mostly formed at warm springs (temperatures above 29°C) when the loss of carbon dioxide causes precipitation in the form of the finest lime particles (so-called bubble stones). Calcareous sinter or onyx marble can also be formed on subterranean freshwater courses in karst areas; better known are the “limestone cones” in caves, the stalactites. 

These are non-marine, chemical sediments that differ mainly in terms of porosity and the proportion of the minerals calcite and aragonite.

While other limestones, such as tufa or travertine, contain calcite or aragonite and are mostly porous, onyx marble is rather compact, has hardly any pores and consists of both calcite and aragonite. Both minerals are chemically identical (CaCO ₃ ), but have a different crystal structure : calcite is trigonal, aragonite is rhombic. According to international nomenclature, onyx marble is therefore mineralogically correctly called calcite-aragonite or aragonite-calcite, while onyx marble is its usual trade name. 

Other names commonly used in retail and wholesale are calcareous onyx, calcite alabaster, ribbon marble, aragonite marble, chalcedony onyx or marble onyx.

Iron and magnesium can be added as minerals . The always present banding is typical as a sign of an alternating deposit of calcite and aragonite; the long, slender and pointed aragonite crystals can usually be seen perpendicular to the sedimentation plane. Onyx marble often comes in shades of white, yellow, orange, red, green, and brown, and every shade in between. The stones from sites that produce a multi-colored picture due to the changing mineral deposits are particularly well and gladly worked on.

 Also have a spectacular effect due to a differentiated play of colors bizarre appearing bulbous or coral-like structures in the level of sedimentation.