There are several different types of building stone. The most common are granite, marble, limestone, travertine and sandstone. Each stone has unique physical acteristics, which affect its applicability to various building designs. This section describes the acteristics and physical properties of the major building stones.

Granite:
Granite is an igneous rock created deep within the earth from magma, cooled slowly under great pressure. It is the hardest building stone with very dense grain, making it virtually impervious to stain. It takes a highly polished finish, which will endure even in inclement environments. It can also be finished in a variety of other ways. There is a broad spectrum of granite colors ranging from nearly pure white to nearly pure black. During its formation, granite may also have been infused with other minerals providing patterned "movement" as well as color.

Marble:

Marble is a metamorphic rock, composed of metamorphosized limestone. In its purest form, marble is crystalline white calcite. Most marbles, however, are infused with impurities such as dolomite, silica or clay, providing variations in color and significant movement. The base colors of marble range from white to black with a broad range of hues. Marble is significantly softer than granite and therefore subject to greater wear and weathering.

Limestone:

Limestone is a sedimentary rock composed of calcites and dolomites. Organic limestones were formed from the deposits of marine shellfish and fossils. Limestone is noncrystalline and possesses very uniform composition, texture and structure. It is soft and ranges in color from white to grey and does not take a polish.

Sandstone:

Sandstone is a sedimentary rock made of compacted sand, held together with calcium, silicon or ferrous materials. Sandstone varies in color, from red to yellow to white, based on the presence of other materials. Sandstone is soft and easy to quarry and shape. It is susceptible to erosion and deterioration from air pollutants. Brownstone is a variety of sandstone.