Granites are a common and very frequent type of felsic intrusive igneous rock. Their crystal structure may vary from middle to large-sized, the color specter can range from pink to gray, depending on their chemical and mineral composition. Usually it can be found in the form of batholith which forms the entire continents. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels which emerge at the contact of hot intruding magmatic material and surrounding rock. Granite is nearly always massive, hard and tough, and therefore it has gained widespread use as a construction (technical) and architectural (decorative) stone. The average density of granite is between 2.65 and 2.75 g/cm but it varies from 1.74 g/cm to 2.80 g/cm.
The word "granite" comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a holocrystalline rock.
Marble (Latin marmor < from Greek) is granulated crystalline limestone with additions. It is the result from the metamorphosis of carbonite prolites (sedimentary rocks of limestone and dolomite) under the conditions of heightened temperature and lythostatic pressure. Pure marble is of snow white color. The additions of metal oxides give it yellow, brown or reddish color, graphite, coal and bitumen grey or black, and chlorite greenish color. If the natural marble plates are spilt with hydrochloric acid, this results in the development of carbon (IV) oxide. Marble is metamorphic rock of granulated (granoblastic) structure and homogeneous, containing calcite and/or dolomite. The primary impurities in the sediment texture give rise to metamorphic minerals (phospherite, pyroxenes). Slate variability of marble rich in phylosilicates is called cipolin. In the antiquity marble was used for the creation of the most beautiful sculptures and the most famous buildings. Sculptures were made from the famous marbles from the Greek island of Paros and from mountain Pentelikon. The most renowned and valued is marble from Carrara in Italy which Michelangelo used for his sculpture of David.
Limestone is a sedimentary rock containing at least 50% of mineral calcite (calcium carbonate, CaCO3) and additional compounds such as: dijaspor, zircon, clay, limonite, hematite, hydrargillite, flintstone, turmaline, sporogelite and granate (and somewhere gramite). Limestone emerged from the sedimentation of shells and skeletal fragments, and sometimes even herbal particles. Pure limestone is white in color. Limestone is composed of very small opaque crystal grains invisible to the naked eye. If containing iron minerals limestone becomes yellowish or reddish, however, coal particles give it dark gray to black color. It easily enters chemical reactions caused by atmospheric factors, it is soluble in water but other insoluble minerals remain at the surface composing ‘terra rossa’ (red soil). Solution of limestone gives cause to numerous characteristic features of Karst such as cracks, karst sinkholes, caves, etc. In nature it can be found as the most frequent component of sedimentary rocks that originate from alluvial sediments containing shells of microscopic protozoa. Of course, the process of sedimentation occurred during vast period of time.