In the same way, the Earth is made up of 70% water and a variety of minerals, chemicals and compounds found in almost the same proportions as those in the human body.
Calcium is one of the most plentiful components found on the Earth's crust, and it is also the main component that makes up several types of rock. Living organisms need the calcium ion Ca2+ to regulate vital cellular processes such as building bones. Calcium in our bones has be replenished through regular intake of calcium-rich dairy goods and vegetables.
Hydroxylapatite is a carbon compound (Ca10(PO4)6(OH)2 that makes up 70% of our bones. It naturally occurs in the Earth as a result of the reaction between limestone and phosphatic solutions derived from guano, droppings from seabirds, bats and seals. In teeth, hydroxylapatite is a complex compound that produces stronger chemicals when exposed to fluoride.
Other calcium compounds such as calcium stearate are extensively used in the construction industry. This white waxy powder does not dissolve in water, which therefore makes it helpful in concrete manufacturing. Calcium stearate limits efflorescence or the process of drying and crystallization of minerals upon exposure to air. It is also used as an additive to food and cosmetics due to its general compatibility with the human body.
Calcium carbonate is considered the most typical compound in industrial applications.
A byproduct of calcium carbonate, Missouri limestone is valued for its strength due to the presence of silica, a main component of glass and its "parent" mineral, quartz. Limestone is also known to contain calcite from the shells of marine life forms that used to reside in such structures when they were still submerged under the ocean. This abundant mineral has been used as a building material since Biblical times.
Like the earth, the body also contains oils and proteins that hold cells and molecules together. Collagen networks like laminin hold cells in their proper places, comparable to the Missouri asphalt and tar that hold brittle stones and concrete together.