Organic Stones
These are organic stones, formed from living things (e.g. plants and animals).
This is a sedimentary (1) rock often containing fossils or shell formations that have collected on the sea floor over very long periods of time. Through tectonic (2) activity over hundreds of millions of years, compression has caused these sediments to transform into limestone rock, and moved them above sea level where they can be mined.
A metamorphic (3) rock comprised or more coarsely grained and re-crystalized calcite (another mineral). It is known that most marbles were limestones that were subject to crystallization through long periods of heating and compression. Most marbles are denser and harder than limestone.
This is a sedimentary (1) rock formed from limestone that had been permeated by very hot water containing calcite. As the water evaporated, crystalized calcite was deposited in this stone, with layers forming over eons of time. Travertine is durable and very hard, and may be used with both inside and outside decorating.
Onyx another form of limestone, formed from the evaporation of cold, leaving behind dissolved calcium (in the form of calcites). Colors are derived from various chemicals that were carried into the stone from water. This stone is very dense, and is often used for walls, counters and flooring.