Black, Pink, Red and White: Why Beach Sand Comes in Different Colours

When we picture a beach, most of us imagine golden sand. But travel a little and you will find beaches that are black as coal, soft pink, deep red or so white they hurt your eyes in the sun. The colour of sand tells the story of where it came from. Here is what gives the world’s beaches their colours, with puzzles of some of the most beautiful examples.

In short: sand takes its colour from what it is made of. Golden sand is mostly quartz stained by iron; white sand is almost pure quartz or crushed coral and shells; black sand is volcanic basalt and glass; red sand is iron-rich cinder that has rusted; pink sand gets its colour from tiny red sea creatures called foraminifera; and green sand comes from crystals of olivine.

Golden sand: pieces of old mountains

Most of the world’s sand, especially on continental coasts, is made mainly of quartz, one of the hardest and most common minerals in rocks such as granite. Over thousands of years, rivers and waves break down rocks into tiny grains and carry them to the sea. Traces of iron and other minerals give the grains their yellow, golden or brownish tones.

Dazzling white sand: silica and coral

Some of the whitest sand on Earth is almost pure silica. Whitehaven Beach in Australia’s Whitsunday Islands is made of about 98 percent silica, so fine and pale that it stays cool underfoot even in the midday sun. At nearby Hill Inlet, the tide swirls it with turquoise water into ever-changing patterns.

In the tropics, many white beaches have a very different origin: coral. Waves break up dead coral and shells, and a surprising amount of this sand comes from parrotfish. As they feed, they bite off pieces of coral, grind them with strong teeth in their throats and pass them out as fine white sand. A single large parrotfish can produce hundreds of kilograms of sand in a year.

Black sand: volcanoes meet the sea

Black sand beaches are found on volcanic islands such as Hawaii, Iceland and Dominica. They form when hot lava flows into the ocean, cools suddenly and shatters into small pieces of dark volcanic glass and basalt, which the waves grind and wash ashore. Because this needs an active or recently active volcano, black sand beaches are often young, and some can disappear within decades if no new lava arrives.

Black sand heats up quickly in the sun, which is one reason green sea turtles in Hawaii like to rest on it. On the rainy east coast of Maui and the black beaches of Dominica, the dark sand makes a striking contrast with bright green forest and white surf.

Red sand: rusted cinders

Red beaches are rare. Kaihalulu, the Red Sand Beach near Hāna on Maui, lies beside an old cinder cone rich in iron. As waves slowly wear away the cone, they carry its red cinders into the small cove below. The iron in them has oxidised over time, much like rust, giving the sand its deep red colour.

Pink sand: tiny red sea creatures

The soft pink sand of Harbour Island in the Bahamas and some beaches in Bermuda gets its colour from foraminifera, microscopic sea creatures with bright red or pink shells. They live on the undersides of reefs, and when they die their shells are broken up by the waves and mixed with white coral sand, giving the beach a gentle rosy glow that is strongest at the water’s edge.

Green sand: a gemstone beach

Even rarer are green beaches. Papakōlea Beach, at the southern tip of Hawaii’s Big Island, gets its olive-green colour from crystals of olivine, a mineral that forms in volcanic rock. Olivine is heavier than other volcanic grains, so the waves carry the lighter material away and leave the green crystals behind. When olivine is of gem quality, it is known as peridot.

Where to find black, pink, red and green sand beaches

• Black sand: Reynisfjara near Vík in Iceland, Punaluʻu on Hawaii’s Big Island, the beaches of Tenerife and Lanzarote in the Canary Islands, the north and east coasts of Bali, and Ureki on Georgia’s Black Sea coast, where visitors come for the dark, magnetic sand rich in magnetite.
• Pink sand: Harbour Island in the Bahamas, Horseshoe Bay in Bermuda, Elafonisi on Crete, the Pink Beach on Padar Island in Indonesia’s Komodo National Park, and Spiaggia Rosa on the island of Budelli in Sardinia, which can now be seen only from a boat.
• Red sand: Kaihalulu near Hāna on Maui, the Red Beach below the volcanic cliffs of Santorini, and the shores of Prince Edward Island in Canada, coloured by iron-rich red sandstone.
• Green sand: Papakōlea on Hawaii’s Big Island and Punta Cormorant on Floreana in the Galápagos Islands, both coloured by olivine.
• White sand: Whitehaven Beach in Australia, the Gulf Coast of Florida, Boracay in the Philippines, and the coral islands of the Caribbean and the Maldives.

Questions people often ask

Why is the sand black in Iceland and Hawaii?

Both are volcanic islands. When lava meets the sea it cools so fast that it shatters into grains of dark basalt and volcanic glass, and the waves pile them up on the shore. At Reynisfjara in Iceland, the black beach lies below cliffs of basalt columns, which come from the same volcanic rock.

Why is the sand so white in Florida and the Caribbean?

The two have different origins. On Florida’s Gulf Coast, around Destin and Siesta Key, the sand is almost pure quartz that rivers carried down from the Appalachian Mountains over thousands of years. In the Caribbean and the Maldives, white sand is made of broken coral and shells, much of it ground up by parrotfish.

Why does white sand stay cool while black sand gets hot?

Light colours reflect most of the sunlight and dark colours absorb it. Pale quartz and coral sand can stay pleasant to walk on even at midday, while black volcanic sand can become hot enough to burn bare feet on a sunny afternoon.

Take only photos

Rare coloured sands are easily lost. In many places, including Hawaii, it is against the law to take sand from the beach, and visitors are asked not to take even a small bottle as a souvenir. The best way to take a black, pink or red beach home is in a photo, or in a jigsaw puzzle.