Where are black sand beaches found?
Black sand is sand that's been turned a black color either by a glossy partly-magnetic mix of sands (usually fine), or by tiny fragments of lava.
Some gold and white beaches can also contain black sand, typically after storms have sorted out grains where heavier, darker particles remain on the surface.
There are many black sand beaches around the world. Prince William Sound, in Alaska, and Lost Coast, California, both have black sand beaches named Black Sand Beach. Hawaii has Kehena Beach, Oneuli Beach, Polulu Valley Beach and Kaimu Beach. Maui hosts Oneuli Beach, Honokalani Black Sand Beach and Waianapanapa Black Sand Beach. Finally, Vik Beach in Iceland has some breathtakingly blue water surrounded by eroded rock formations beyond a beach of black sand.
For more black sand beaches, try a Web or Image search on Google or your favorite search engine for black sand beach. You'll be stunned by some of the amazing photos.
Because they are made of black volcanic sand rather than white coral sand or white quartz/limestone sand. However, Japan has also many white sand beaches, which are made of white coral sand (southern islands) and white quartz/limestone sand (peninsulas on mainlands). White sand beaches in Japan: http://www.flickr.com/photos/ippei-janine/sets/72157600321338295/ There are also black sand beaches in volcanic countries such as Hawaii and Iceland.
Beaches form when tiny bits of rock that have been eroded by the action of the waves wash up on shore. They are different because they tend to be composed of different types of sand (rock bits). For example, beaches formed mainly of lava rock will have black sand, while other beaches may be white, pink, or tan.
There are several black sand beaches in NZ. The most famous would be Piha. The beaches along the west coast of the North Island above Mt Taranaki have black sand due to iron rich sediment being washed out from around the volcano. These include: Bethells, Muriwai, Karekare, Whatipu, Piha and the little ones in between like White's, Maori Bay etc.
Generally sand is found on beaches that are formed with rocks and minerals, especially with access to life, such as trees and coral sea animals. Sand is created by continued sea action. What is found on Antarctica's beaches is more aptly described as rubble, some volcanic, and is most often described as pebbles. The sea ice around the Antarctic continent freezes annually, minimizing sea action that produces particles as small as sand.
Not all sand is white. There is some white sand, but a number of other shades exist from tan to black. The white sand at White Sands National Monument is white because of the gypsum in it, while the white sand of beaches in the remote oceans is composed largely of calcium carbonate from shell and coral fragments. Tan or beige sand is often quartz, and black volcanic sand is rich in basalts and obsidian.