CLASIFICATION OF STONES

It is important to have at least a basic understanding concerning the geology of the dimensional stones being used commercially.


All stone is not the same, there are three major groups from which the stones that are used for decorative and finishing purposes come from. The difference between and within these stone groups has a dramatic effect on the performance of a stone. These differences are attributed to mineral components and the processes by which the stone was formed.


MINERAL STONE COMPONENT:


     Stones are made up of a mosaic of interlocking mineral grains that have definite chemical compositions. Minerals have been divided into groups. The groups we are primarily concerned with are the common rock-forming mineral groups which can be subdivided into two mineral categories Silicates and the Carbonates.


     Silica is the most common chemical component of the earth. Silicates which contain silica are generally the harder minerals and the most common rock-forming minerals.These stones can be referred to as Siliceous based stones.

     Carbonates are the next most important minerals in the rock-forming group. This mineral group generally contains the softer minerals. These stones can be referred to as Calcareous based stones.