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Calcium is dull gray, but it is shiny when scratched. Other physical properties. Calcium is an excellent conductor of electricity. It is very soft and easily scratched. Chemical properties. Calcium reacts rapidly with air to form a coating of gray oxide, and it burns with a red flame.
CALCIUM. Calcium is an important part of bones and teeth. It is essential in soft tissues and blood for regulating the functions of muscles and nerves. The calcium in the blood, although small in amount, is necessary for the clotting of blood, and it assists in regulating the functioning of muscles and nerves.