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HISTORY: The ancient Romans used limestone. They found when heating it you calcium oxide, which cement. They called it Calx, which is where the word calcium comes from. They used lime to make mortar, which held their bricks together. They used calcium hydroxide to make fertilizers for their crops and they used calcium to make plaster, glue and bricks. Sir Humphrey Davy discovered the pure form of calcium in 1808.

GENERAL INFO: Calcium is # 20 so on the Periodic Table of Elements, it is always found in ionic compounds, in some rare occasions it can make Blue John.it is the fifth most abundant element on the Earth’s crust. Calcium is in period four and is an alkaline earth metal. Calcium is found in most rocks, limestone, bones and shells of shellfish. It has two valence electrons, four shells and it has a positive 2 charge. In it’s pure form it looks like little silver deer poops and will react with oxygen in the air.

LIMESTONE: Limestone was used a lot by ancient Romans and are rocks made mostly of calcium carbonate. It is made from reefs and cemented remains of sea creatures. Oolitic limestone is made from millions of tiny balls of limestone joined together to make a rock. Limestone is porous and has lots of cracks. Depending on the amount of iron in limestone it can be many different colors. It can be green, grey and if a lot of iron is present then a honey color. Calcium compounds can also make crystals called Blue John.