Question: are teeth harder than diamonds?
Answer: Using the scale of mineral hardness developed by German mineralogist Frederich Mohs in 1812, tooth enamel ranked 5 out of the 1-10 values. Diamonds ranked 10 (hardest) and plaster of Paris ranked only 2 on the Moh's scale. Tooth enamel was also found to be harder than limestone and most shells containing calcite.