Travertine is a type of carbonate stone often found in limestone and formed by the evaporation of mineral-rich water either coming up om a hot spring or alkali lake or in a cave system. 

Travertine is known also as banded calcite in some applications. It is also known as banded onyx and used in jewelry and building applications. Limestone cave formations are made of travertine and result in a gemstone called "cave onyx" which often has microbialite speleothem growth patterns within it like scallops, plumes and flowers. 

A primary component of Bumblebee "Jasper" is sulphur and arsenic rich travertine deposits from an active fumerole in Java, Indonesia.