Natural stone is a geographical list of stone used for decorative purposes in construction and monumental sculpture. Natural and precast stones vary significantly in their geographic origin, mineralogical composition, and physical and mechanical properties. There are numerous types of stone to select, with each one exhibiting specific qualities of compressive strength and abrasive resistance.

 

Granite - is a common and widely occurring type of intrusive, felsic, igneous rock. granite usually have a medium to coarse granited texture. A granitic rock with a porphyritic texture is sometimes known as a porphyry. Granite can be pink to dark gary or even black, depending on their chemistry and mineralogy. Outcrops of  granite tend to form tors and rounded massifs. Granite sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole. Granite is nearly always massive, hard and tough, and therefore it has gained widespread use as a construction stone.

 

Marble - is a non foliated metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite. It is extensively used for sculpture as a building material, and in many other applications.

 

Limestone - is a sedimentary rock composed largely of the mineral calcite. Like most other sedimentary rocks, limestones are comprised of grains, however, around 75%-90% of limestone grains are skeletal fragments of marine organisms such as coral or foraminifera. Other carbonate grains comprising limestones are ooids, peloids, intraclasts and extraclasts and extraclasts. Limestone males up about 10% of the total volume of all sedimentary rocks. limestone may also form in both lacustrine and evaporite depositional environments.

 

Sandstone - is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Some sandstones are resistant to weathering, yet are easy to work. This makes sandstone a common building and paving material. Because of the hardness of the individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which make grindstones for sharpening blades and other implements.

 

Travertine - is a banded, compact variety of limestone formed along streams, particularly where there are waterfalls and around hot or cold springs. Calcium carbonate is deposited where evaporation of the water leaves a solution that is supersaturated with chemical constituents of calcite.Tufa, a porous or cellular variety of travertine, is found near waterfalls. Coquina is a poorly consolidated limestone composed of pieces of coral or shells.

 

Slate - is a fine grained, foliated, homogeneous metamorphic rock derived from an original shale type sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering. Slate is frequently grey in color especially when seen en mass covering roofs.

 

General Characteristics of Stone - The complex nature and variables of natural and precast stone make it difficult to generalize their overall physical and mechanical properties. Unless the operator has the experience in cutting a particular kind of stone, there are methods that can help predict the stone's cutting performance and determine the best selection of diamond blade. The American Society of Testing and Materials (ASTM) recognize several physical property measurments that can be very helpful to identify a stone's hardness.