Calcium 20 Ca 40.078(4)   Switch element to... actinium aluminium aluminum americium antimony argon arsenic astatine barium berkelium beryllium bismuth bohrium boron bromine cadmium caesium calcium californium carbon cerium cesium chlorine chromium cobalt copper curium darmstadtium dubnium dysprosium einsteinium erbium europium fermium fluorine francium gadolinium gallium germanium gold hafnium hassium helium holmium hydrogen indium iodine iridium iron krypton lanthanum lawrencium lead lithium lutetium magnesium manganese meitnerium mendelevium mercury molybdenum neodymium neon neptunium nickel niobium nitrogen nobelium osmium oxygen palladium phosphorus platinum plutonium polonium potassium praseodymium promethium protactinium radium radon rhenium rhodium roentgenium rubidium ruthenium rutherfordium samarium scandium seaborgium selenium silicon silver sodium strontium sulfur sulphur tantalum technetium tellurium terbium thallium thorium thulium tin titanium tungsten ununbium ununhexium ununoctium ununpentium ununquadium ununtrium uranium vanadium xenon ytterbium yttrium zinc zirconium Go adjacent... Na Mg   K Ca Sc Rb Sr Y

Geological information

Abundances

In this table values are given in units of ppb (parts per billion; 1 billion = 10⁹), both in terms of weight and in terms of numbers of atoms. Values for abundances are difficult to determine with much certainty, so all values should be treated with some caution, especially so for the less common elements. Local concentrations of any element can vary from those given here by orders of magnitude.

View graphs	Abundance	ppb by weight	ppb by atoms
	Universe	70000	2000
	Sun	70000	2000
	Meteorite (carbonaceous)	11000000	5200000
	Crustal rocks	50000000	26000000
	Sea water	4220	650
	Stream	1500	38
	Human	14000000	2200000

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Notes

Calcium metal is never found as the free metal in nature. Calcium is fifth in abundance in the earth's crust, of which it forms more than 3%. It occurs as limestone (CaCO₃), gypsum (CaSO₄.2H₂O), and fluorite (CaF₂). Apatite is calcium fluorophosphate or chlorophosphate.

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