Onyx

Natural stone gets the respected classification of marble due to sharing the same mineral makeup as others. It consists of calcite, which also happens to be present in limestone, marble, and travertine models. Onyx Stone is formed from spring water or groundwater with a considerable degree of calcite dissolved in it. Travertine is formed like that of onyx. The main difference, as far as texture is concerned, is that travertine has a porous, lace-like surface, whereas onyx is quite smooth and non-porous. Other than that, these two stones share many commonalities.