Limestone is defined as a rock of sedimentary origin composed mainly of calcium carbonate or the double carbonate of calcium and magnesium, or a combination of both minerals.
Re-crystallized limestone’s, compact microcrystalline limestone’s, and travertine’s that are (capable) of taking a polish are (promoted), marketed and sold as either limestone or marble, mainly in the United States.
Dimension limestone is divided into three (sub- classifications) that describe their densities in the approximate ranges as listed :
Low Density : Limestone with a density ranging from 110 through 135 lb/ft3 (1760 through 2160 Kg/M3).
Medium Density : Limestone having a density greater than 135 but not greater than 160 lb/ft3 (2160 through 2560 Kg/M3).
‘High Density : Limestone having a density greater than 160 lb/ft3 (2560 Kg/M3).
Limestone contains a number of distinguishable natural characteristics, including calcite spots or streaks, fossils or shell formations, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertine-like formations and grain formation changes. One or a combination of these characteristics will affect the texture.