Most people think of as white and chalky, but it's actually a silver, shiny metal

Calcium

Calcium is actually a shiny, silvery metal under standard conditions. However, it quickly forms a gray-white oxide on its surface when exposed to air after being cut. 

Calcium is mostly found on Earth in the form of rocks and minerals such as limestone (calcium carbonate), dolomite (calcium magnesium carbonate), and gypsum (calcium sulfate). It rarely exists in its pure elemental form in nature.