12 Interesting Facts about Calcium: Alkaline Earth Metal Atomic Element Number 20

1 Calcium in its pure form is nothing like the white hard stuff we associate with bones or seashells. Calcium if in fact a pale grey, softish metal with a dull lustre.

2 Calcium is the fifth most abundant element found in the earth’s crust, the fifth most abundant ion dissolved in seawater and also the fifth most abundant element in the body (after hydrogen, oxygen, carbon and nitrogen). But being so reactive, calcium is seldom found in its pure state, only within compounds.

3 We couldn’t do without calcium. Our bones and teeth are made from calcium phosphate. The skeleton is constantly replenishing itself just like our skin, but at a slower rate. To maintain healthy bones humans need at least 1000mg of calcium a day (more if young, old or pregnant). Foods rich in calcium include dairy, dark greens and beans.

Powdered Calcium Carbonate

4 Calcium Facts

Atomic number: 20

Atomic weight: 40.078

State: silver-grey solid

Category: alkaline earth metal

Melting point: 842°C (1,548°F)

Boiling point:  1,484°C (2,703°F)

Why the White Cliffs of Dover are White

5 The White Cliffs of Dover consists of calcium hydroxide and calcium carbonate. These chalky composites are produced when calcium is exposed to the air. If calcium was prone to this oxidization, this striking landmark might be known as the Grey Cliffs of Dover instead, which doesn’t have the same ring.

6 Houses couldn’t be built without calcium. It is used in glass, bricks and building mortar (or lime plaster). Lime plaster, or calcium oxide, as it is technically known, has been used since Roman times (which was then known as calx). Mixed with sand and water will produce cement that hardens as carbon dioxide in the air is absorbed. Georgian architecture provides the most aesthetically pleasing examples of limestone, some of which were formed during the Jurassic age.

Acid Soil and Alkaline Soil

Calcium Symbol

7 Confused about acid versus acid soil? Well, alkali soil contains a lot of calcium in the form of lime, which has a chalky consistency and tends to be dry. Acid soil might be clumpy or peaty due to excessive water washing the lime away. Plants cannot absorb nutrients very well if the soil is too acidic. Lime is often added to acid soil to raise the PH level. An acid testing kit will help give an accurate reading of the soil.

Is Calcium Toxic?

8 Calcium as a mineral supplement can cause kidney stones and diarrhea if taken in high doses. However, calcium metal is a different matter. It is toxic if ingested and is highly reactive when in contact with water, producing hydrogen. In the form of calcium hypochlorite, (a bleaching agent and sanitizer of drinking water), can spur rapid decomposition if placed in a warm place which will release poisonous chlorine gas.

Calcium in the Earth’s Crust

9 Calcium can be found in many natural compounds as well as lime and in the soil, these include gypsum, carbonate rocks, chalk, fluorite, sediments, dolomite, marble and calcite. It can also be found in the limestone caves of stalagmites and stalactites, not forgetting the hard matter of crustaceans and fossils.

10 Calcium is also put to industrial and commercial use, as calcium nitrate (fertilizer), calcium hypochlorite (chlorine powder for bleaching), calcium carbide (used in carbide lamps and as a plant ripening agent), calcium sulphate (a food additive), calcium citrate (citric acid) and many others.

Who Isolated Calcium Element?

11 Despite being used for thousands of years, calcium was not isolated into its pure state until 1808 by Sir Humphry Davy when he electrolyzed a mixture of lime and mercury oxide.

12 The expression ‘being in the limelight’ comes from an early form of stage lighting. In the 1800s, lime (calcium oxide) was burnt in an oxygen-hydrogen flame to produce a brilliant white light for the theatre. The expression stuck.