How hard is tooth enamel compared to other materials? © Getty Images

How hard is tooth enamel compared to other materials?

Tooth enamel is harder than steel, but breaks much easier.

Asked by: Ron Pirani, Massachusetts, US

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Tooth enamel is mostly hydroxyapatite, which is a mineral form of calcium phosphate. The apatite group of minerals scores a five on the Mohs hardness scale; which makes enamel the hardest biological material. Tooth enamel is harder than steel, but a lot more brittle. So you can’t scratch your enamel on metal cutlery but you can chip it by trying to open a beer bottle with your teeth.


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