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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 is essential to bone health. It is the most abundant mineral in the body and helps build and support strong bones. Other important functions dependent on calcium include: muscle contraction, regulation of heartbeat, and blood clotting.