horns and scouring out sand to form cusps. This forms the uneven face on some sand shorelines. White sand beaches look white because the quartz or eroded limestone in the sand reflects or scatters sunlight without absorbing other colors. Sand colors The composition of the sand varies depending on the local minerals and geology. Some of the types of sand found in beaches around the world are: White sand: Mostly made of quartz and limestone , it can also contain other minerals like feldspar and gypsum . Light-colored sand: This sand gets its color from quartz and iron , and is the most common sand color in Southern Europe and other regions of the Mediterranean Basin , such as Tunisia . Tropical white sand: On tropical islands, the sand is composed of calcium carbonate from the shells and skeletons of marine organisms, like corals and mollusks , as found in Aruba . Pink coral sand: Like the above, is composed of calcium carbonate and gets its pink hue from fragments of coral, such as in Bermuda and the Bahama Islands . Black sand: Black sand is composed of volcanic rock, like basalt and obsidian, which give it its gray-black color. Hawaii 's Punaluu Beach, Madeira's Praia Formosa and Fuerteventura's Ajuy beach are examples of this type of sand. Red sand: This kind of sand is created by the oxidation of iron from volcanic rocks. Santorini 's Kokkini Beach or the beaches on Prince Edward Island in Canada are examples of this kind of sand. Orange sand: Orange sand is high on iron. It can also me a combination of orange limestone, crushed shells, and volcanic deposits. Ramla Bay in Gozo , Malta or Porto Ferro in Sardinia are examples of each, respectively. Green sand: In this kind of sand, the mineral olivine has been separated from other volcanic fragments by erosive forces. A famous example is Hawaii's Papakolea Beach , which has sand containing basalt and coral fragments. Olivine beaches have high potential for carbon sequestration , and artificial greensand beaches are being explored for this process by Project Vesta . Erosion and accretion Natural erosion and accretion Causes Beaches are changed in shape chiefly by the movement of water and wind. Any weather event that is associated with turbid or fast-flowing water or high winds will erode exposed beaches. Longshore currents will tend to replenish beach sediments and repair