How is Sand Formed?

There is an abundance of sand in the world, just think of all those deserts and sand dunes around, not to mention beaches! With so much sand in the world it’s easy to forget that it takes millions of years and lots of work to create each tiny grain.

Sand is created through the gradual weathering of rocks into smaller and smaller pieces. These pieces of rock are then transported by wind and water, where they are further broken down. By classification sand particles fall between the size of the larger gravels and the smaller silt and clay particles.

Sand can vary depending on the kind of rock that it starts it life as. The sand that we’re used to is the most commonly occurring and is created through the weathering of granite. Not all minerals are strong enough to survive the weathering process so the end result is predominantly composed of quartz and feldspar. Although quartz is quite a clear mineral, it often has iron oxide attached to it, giving the sand the tan colour that we recognise.

However, in other parts of the world the sand can vary in colour and composition enormously. In tropical islands, the bright white beaches exist because there is a very limited presence of quartz . Instead, the sand is created from the calcium carbonate in the corals, as the shells and skeletons of the animals living in the reefs are broken down.

Whereas, in Hawaii, the iconic black beaches are created from the volcanic eruptions that occur on the island. As the lava travels down the volcanoes, it cools and then breaks up when in contact with the sea. This type of sand is created from basalt rocks and volcanic gases, which are normally dark in colour. However, they are very susceptible to weathering and therefore do not last as long as quartz sand. The Hawaiian government has even had to ban people from removing black sand in order to help maintain their beaches.

Sand is very much a fingerprint of the area it is found in. No two areas are likely to have the same sand as each place has different source materials, different levels or weathering and different mineral compositions. Therefore every grain of sand truly is unique!