Stone Info

Flagstone is a generic description for a flat stone that is most often used in building and landscaping. It is a sedimentary stone that is split into thin layers, allowing it to be used in many applications. Flagstone is usually a sandstone containing feldspar and quartz, often cemented together with calcium, silica or iron oxide. Flagstone is not to be confused with slate, which is also a sedimentary rock but composed primarily of clay or volcanic rock.

Limestone is a sedimentary rock composed largely of the mineral calcite (calcium carbonate: CaCO3). Limestones often contain variable amounts of silica in the form of chert or flint, as well as varying amounts of clay, silt and sand as disseminations, nodules, or layers within the rock. The primary source of the calcite in limestone is most commonly marine organisms. These organisms secrete shells that settle out of the water column and are deposited on ocean floors as pelagic ooze or alternatively is conglomerated in a coral reef (see lysocline for information on calcite dissolution). Secondary calcite may also be deposited by supersaturated meteoric waters (groundwater that precipitates the material in caves). This produces speleothems such as stalagmites and stalactites. Another form taken by calcite is that of oolites (oolitic limestone) which can be recognised by its granular appearance. Limestone makes up about 10 percent of the total volume of all sedimentary rocks.

Granite is—quite literally—as old as the earth. It is formed from liquid magma, the molten rock still found at the core of the planet, cooled slowly to form a substance approaching the hardness and durability of diamond. Granite is an igneous rock, the name reflecting its fiery beginnings. The chemical composition of granite is similar to that of lava. However, granite owes its hardness and density to the fact that it has been solidified deep within the earth, under extreme pressure. Over the eons, seismic activity has changed the crust of the planet, forcing veins of granite to the surface. Glaciers scraped off layers of dirt, sand and rock to expose granite formations. Typically revealed by outcrops, the deposits have been discovered on all the continents.

• Feldspar (50% or greater)
• Quartz (25-40%)
• Mica (3-10%)

ne may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, quartz, dolomite or barite may line small cavities in the rock. Folk and Dunham classifications are used to describe limestones more precisely.

 

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AlAll prices subject to change without notice _________________________2006 Stone Engraving _______________________________________07/02/2006