What is Calcium? Origin / Meaning of the name Calcium
The name 'Calcium' originates from the Latin words ‘calx’ or 'calcis' meaning limestone. Calcium compounds, such as marble, chalk, lime (calcium oxide), limestone (calcium carbonate) and gypsum have been used in construction and for decoration since antiquity.

What is Calcium? Periodic Table Group and Classification of the Calcium Element
Elements can be classified based on their physical states (States of Matter) e.g. gas, solid or liquid. This element is a solid. Calcium is classified as an "Alkaline Earth Metals" which are located in Group 2 elements of the Periodic Table. An Element classified as an Alkaline Earth Metals are found in the Earth’s crust, but not in the elemental form as they are so reactive. Instead, they are widely distributed in rock structures. For additional facts and information refer to Calcium Properties.

Common properties of Alkaline Earth metals
The elements classed as "Alkaline Earth metals" have the following properties in common:

• Shiny Solids
• Two electrons in the outer shell
• Can conduct heat or electricity
• Can be formed into sheets

Nearly 75% of all the elements in the Periodic Table are classified as metals which are detailed in the List of Metals.

Facts about the History of the Discovery of the Calcium Element
Compounds of calcium such as limestone, chalk, marble and gypsum plaster have been in use since antiquity. The Ancient Romans discovered concrete by combining a mixture of lime (calcium hydroxide) with volcanic ash and a few pieces of rock. Without concrete fabulous Roman buildings such as the Pantheon and the Colosseum could not have been built. In 1808 Sir Humphry Davy isolated the element Calcium by the electrolysis of a mixture of lime and mercuric oxide (HgO).

Sir Humphry Davy (1778 - 1829)

What is Calcium? Occurrence of the Calcium Element
3.5% of Earth's crust
Fifth most abundant element in the earth's crust
Obtained from chalk, limestone and marble
Only found in living organisms

Abundances of the element in different environments
% in Universe 0.007%
% in Sun 0.007%
% in Meteorites 1.1%
% in Earth's Crust 5%
% in Oceans 0.00042%
% in Humans 1.4%

Medical Uses of Calcium - Health and Treatments
Interesting information is contained in the following table of Medical Uses of Calcium, Health and Treatments. Calcium supplements are useful for preventing osteoporosis and possibly colon cancer. It is also used for treating PMS, colon polyps and in lowering high blood pressure.
 

A useful reference providing information regarding the medical uses of Calcium, associated health issues and disorders and treatments using calcium preparations.

Associated Uses of Calcium
Dairy products are an excellent source of calcium. Deficiency can affect bone and teeth formation
Vitamin D is needed to absorb calcium
Reducing agent
Medicine and Health Care
Alloying agent used in the production of alloys
Coral calcium , calcium carbonate, chloride, citrate, carbide, hydroxide
Calcium oxide (lime, quicklime) (CaO). Lime is prepared by strongly heating calcium carbonate (limestone) in large furnaces called kilns.
Pure calcium hydroxide is a light white powder. It is sparingly soluble in water, forming a solution called limewater, which is often used in medicine as a mild alkali.
Cement. When limestone to which clay and sand have been added in certain proportions is burned until it is partly fused (some natural marl is already of about the right composition), and the clinker so produced is ground to powder, the product is called cement.
Bleaching powder (CaOCl2). When Chlorine acts upon a solution of calcium hydroxide the reaction is similar to that which occurs between chlorine and Potassium hydroxide.