The islands are covered with a thin layer off soil consisting of a mixture of sand and changing quantities of organic matter, which imparts colour ranging from light brown, to very dark brown, nearly black and to pure white. It often retains the parental coral rock, in the form of broken pieces of varying size. Below this topsoil is hardened and compressed sand or sandstone and further down is sand or coral rock. In most islands the soil has a poor water-retaining capacity and is highly alkaline due to an excess of calcium from the basal coral rock. Most islands have fresh water at a little depth, easily obtained by sinking shallow wells.
More on:http://www.freelancewriter.org.uk/images/Maldives.pdf, www.maledivy.sk