Black sand

Black sand is sand that is black in color. One type of black sand is a heavy, glossy, partly magnetic mixture of usually fine sands containing minerals such as magnetite, found as part of a placer deposit. Another type of black sand, found on beaches near a volcano, consists of tiny fragments of basalt.
While some beaches are predominantly made of black sand, even other color beaches (e.g. gold and white) can often have deposits of black sand, particularly after storms. Larger waves can sort out sand grains leaving deposits of heavy minerals visible on the surface of erosion escarpments.
Placer deposits
Black sands are used by miners and prospectors to indicate the presence of a placer formation. Placer mining activities produce a concentrate that is composed mostly of black sand. Black sand concentrates often contain additional valuables, other than precious metals: rare earth elements, thorium, titanium, tungsten, zirconium and others are often fractionated during igneous processes into a common mineral-suite that becomes black sands after weathering and erosion.
Several gemstones, such as garnet, topaz, ruby, sapphire, and diamond are found in placers and in the course of placer mining, and sands of these gems are found in black sands and concentrates. Purple or ruby-colored garnet sand often forms a showy surface dressing on ocean beach placers.
An example of a non-volcanic black sand beach is at Langkawi in Malaysia.
Basalt fragments
When lava contacts water, it cools rapidly and shatters into sand and fragmented debris of various size. Much of the debris is small enough to be considered sand. A large lava flow entering an ocean may produce enough basalt fragments to build a new black sand beach almost overnight. The famous "black sand" beaches of Hawaii, such as Punaluʻu Beach and Kehena Beach, were created virtually instantaneously by the violent interaction between hot lava and sea water. Since a black sand beach is made by a lava flow in a one time event, they tend to be rather short lived since sands do not get replenished if currents or storms wash sand into deeper water. For this reason, the state of Hawaii has made it illegal to remove black sand from its beaches. Further, a black sand beach is vulnerable to being inundated by future lava flows, as was the case for Hawaiʻi's Kaimū, usually known simply as Black Sand Beach, and Kalapana beaches. An even shorter-lived black sand beach was Kamoamoa. Unlike with white and green sand beaches, walking barefoot on black sand can result in burns, as the black sand absorbs more solar radiation.
Beaches
Black sand has formed beaches in places including:
Europe
Bulgaria
Burgas
Faroe Islands
Tjørnuvík
Italy
Ladispoli
Naples
Stromboli
Georgia
Ureki
Greece
Perivolos beach, Santorini
Cyprus
Governor's Beach, Limassol
Iceland
Vík í Mýrdal
Reykjanes
Stokksnes
Portugal
Azores
São Roque, São Miguel
Mosteiros, São Miguel
Madeira
Spain
Tenerife
Playa El Bollullo, near Puerto de la Cruz
Playa Jardín, Puerto de la Cruz
Playa Las Gaviotas near Santa Cruz
La Palma
Playa de Los Cancajos, Breña Baja
Fuerteventura
Playa de Ajuy
Playa Pozo Negro
Galicia
Praia de Teixidelo, Cedeira (non-volcanic)
Africa
Egypt
Algeria
Cameroon
Limbe
Idenau
Debundscha
North America
Canada
Black Beach, Lorneville, New Brunswick (near Coleson Cove Generating station, west of Saint John)
Salmon Cove Beach, Conception Bay, Newfoundland
Mexico
Playa Patzcuarito (Nayarit)
Playa La Ventanilla (Oaxaca)
United States
Black Sand Beach, Prince William Sound, Alaska,
Lowell Point Beach, Seward, Alaska
Black Sand Beach, Lost Coast, California
Central America
Costa Rica
Playa Negra, Guanacaste
Playa Negra, Puerto Viejo, Limón
Guatemala
Puerto de San José, Monterrico, Champerico, Puerto Quetzal
Panama
Las Lajas, Chiriquí Province
El Salvador
Playa El Tunco
Caribbean
Saint Vincent and the Grenadines
Montserrat (most beaches except Rendezvous Beach)
St. Eustatius
St. Kitts
Nevis
Jamaica
Dominica (most beaches)
Martinique (most North east Beaches and Anse Noire beach)
St. Lucia
Anse Chastanet
Guadeloupe
Grand Anse beach, Basse-Terre
Grenada
Venezuela
Barranquilla, Colombia
St.Thomas (USVI)
Puerto Rico (US)
Barceloneta, Machuca's Garden
Playa Negra in Vieques
Dominican Republic
Cocolandia, Palenque Beach, San Cristóbal
Baní Sand Dunes, Peravia, Baní
Black Stone Beach, Santa Cruz, Aruba
Asia
Alappad, Kollam, Kerala, India
Valsad, India
Hac Sa Beach, Macao
Hunza River, Pakistan
Jambi, Indonesia
Langkawi, Malaysia
Lung Kwu Tan, Hong Kong
Kaohsiung, Taiwan
Yilan, Taiwan
Akyab, Arakan
Kaladan River, Chin State and Rakhine State, Myanmar
Lingayen Gulf, Philippines
North Atlantic
Reynisfjara, Iceland
North Pacific
Iwo Jima
Kugenuma Kaigan, Japan
Hawaiʻi nei
"Big Island"
Isaac Hale Beach Park (Pohoʻiki)
Kaimū (destroyed by lava flow in 1990, now a new black sand beach is forming)
Kehena Beach
Punaluʻu Beach
Richardson Beach, Hilo
Waipiʻo Beach
Maui
Honokalani Black Sand Beach and Waiʻanapanapa Black Sand Beach in Waiʻanapanapa State Park
Oneʻuli Beach also known as Naupaka Beach
South Pacific
Guam
Talafofo
New Zealand (listed from North to South)
Muriwai
Bethells Beach
Anawhata
Piha
Karekare
Whatipu
Karioitahi Beach
Raglan
Taranaki region, New Zealand
Wellington region, New Zealand
Tahiti
Tautira
Point Venus
Papua New Guinea
Gulf of Papua
Indian Ocean
South coast of Java, Indonesia (ironsand)
See also
Diamond
Heavy mineral sands ore deposits
Ironsand
Mining
Placer deposit
References
Sand
Economic geology
Sediments
Beaches of Alaska