A Visual Encyclopedia of the Periodic Table

42

Alkaline Earth Metals

Forms

contain the compound calcium phosphate.

The hard, outer layers of many other animals,

such as the shells of sea snails, are made of

calcium carbonate. Calcium is very important

in our diet. We get calcium by eating calcium-

rich food, including dairy products, green

The most abundant metal in the human

body, calcium is also the fifth most

common element on Earth. It appears in

many minerals: calcite and aragonite are made

of a compound of calcium and carbon called

calcium carbonate. Bones in animal skeletons

Calcium 20 20 20 State: SolidDiscovery: 1808

Ca

20

These column-

shaped cr ystals

contain calcium

carbonate.

Bones are hardened

by calcium phosphate.

Calcite

Aragonite

Large,

fang-like

cr ystals

This cr ystal has a

shiny surface. This pure

metal is soft

enough to cut

with a knife.

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042_043_Calcium.indd 42 12/12/16 5:37 pm