Lucite Cube // Calcium

Calcium - known to every schoolkid as some vaguely healthy substance in milk and cheese - is an element whose true nature is much unknown to most. It's actually a metal that simply cannot exist in nature uncombined with other elements because it is too reactive. That is, too willing to pair its atoms with other atoms to form molecules. The little tramp.

The CaCO3 form gives us both chalk and marble, while the slightly different CaSO4 is much better known as the sheet rock that lines most American homes.

Even your very bones are a brew of calcium phosphates. It might be a surprise to learn calcium is a metal, but if you read through the ingredients on plenty of foods, you'll also see iron, magnesium, and other metals that your body needs.

Although it's lightweight and plentiful, you'll never see calcium used the way we use other metals on Earth. It would instantly sizzle and dissolve on contact with water or atmosphere. But it would be great for building on say, the Moon.

Don't worry though, this sample is stored in argon to keep that delicate luster alive for all eternity. In its glass cage, this piece of calcium rolls around like a popcorn. The mind takes a while to adjust the sight of metal as light as a feather.