Martineli

COAL: A sedimentary rock, formed from decayed plants, is mainly used in power plants to make electricity.
LIMESTONE: A sedimentary rock, it is used mainly in the manufacture of Portland cement, theproduction of lime, manufacture of paper, petrochemicals, insecticides, linoleum, fiberglass, glass, carpet backing and as the coating on many types of chewing gum.
SHALE: A sedimentary rock, wellstratified in thin beds. It splits unevenly more or less parallel to bedding plane and may contain fossils. It can be a component of bricks and cement.
CONGLOMERATE: A sedimentary rock with a variablehardness, consisted of rounded or angular rock or mineral fragments cemented by silica, lime, iron oxide, etc. Usually found in mostly thick, crudely stratified layers. Used in the constructionindustry.
SANDSTONE: A sedimentary rock more or less rounded. Generally thick-bedded, varicolored, rough feel due to uneven surface produced by breaking around the grains. Used principally forconstruction, it is easy to work, the red-brown sandstone of Triassic age, better known as "brownstone," has been used in many eastern cities.
GRANITE: An igneous-plutonic rock, medium to coarse-grained that ishigh in silica, potassium, sodium and quartz but low in calcium, iron and magnesium. It is widely used for architectural construction, ornamental stone and monuments.
PUMICE: An igneous-volcanicrock, it is a porous, brittle variety of rhyolite and is light enough to float. It is formed when magma of granite composition erupts at the earth’s surface or intrudes the crust at shallow depths. It isused as an abrasive material in hand soaps, emery boards, etc.
GABBRO: An igneous-plutonic rock, generally massive, but may exhibit a layered structure produced by successive layers of differentmineral composition. It is widely used as crushed stone for concrete aggregate, road metal, railroad ballast, etc. Smaller quantities are cut and polished for dimension stone (called black granite)....