There are two main types of limestone on the island: «alveo» lime, of organic origin, formed by the cementation of skeletal remains and shells, and «cuchara» lime, resulting from the precipitation of calcium bicarbonate. The extraction of these stones is done in open pits using manual tools such as bars, picks, wedges, and hoes. The stones are extracted from stratified deposits and, once collected, are transported again by camels. The selection of the stone is crucial since the quality of the lime depends on the stone used and how it has been previously treated.