Sedimentary stone came from organic elements such as glaciers, rivers, wind, oceans, and plants. Tiny sedimentary pieces broke off from these elements and accumulated to form rock beds. They were bonded through millions of years of heat and pressure.
A sedimentary rock that began as limestone (calcium carbonate), which over time was heated by the Earth’s core, releasing pressurized water and steam to form hot springs. The rising hot water would dissolve the limestone and bring with it granules of stone from below the surface that collected into mud baths. When this mud cooled, it would crystallize into solid stone, now called travertine. The stone is often light in color and beautifully banded as a result of the presence of iron compounds or other organic impurities
Limestone is a common sedimentary rock composed primarily of the calcium carbonate mineral, calcite (CaCO3). Limestone constitutes approximately 10 percent of the sedimentary rocks exposed on the earth’s surface.
Limestone is formed either by direct crystallization from water (usually seawater), or by the accumulation of sea animal shells and shell fragments. In the direct crystallization case calcium ions in the seawater combine with atmospheric or dissolved carbon dioxide to form calcium carbonate, which being insoluble, precipitates out. Over time, layers of the calcium carbonate form, and with sufficient time and pressure from overlying materials, are transformed to solid rock.