Flints and the Chalk Reef

Seawater contains many things dissolved in it. Salt, of course, is by far the commonest mineral in seawater, but there is also iron, calcium and silica for example in much smaller amounts. Some animals like fish and corals and crabs extract the calcium from the sea, and concentrate it to make bones and shells, whereas others like sponges extract and concentrate the silica to make their skeletons. Flint is the glass-like material which originally came from sponge spicules, tiny structures that make up the sponge skeleton.

Flint Knapping

Flint is made from silicon, the second most common element on Earth. Flint can be found in a variety of shapes and sizes, ranging from small pebbles to large stones and even thick sheets. Flint knapping is the traditional skill of making stone tools. In the distant past hunter-gatherers relied on this amazing skill to make their tools and hunting implements.

Flint is useful in other ways, and we still use it today. You will see lots of flint walls in and around Norfolk.