The Mohs scale was created in 1812 by the German geologist and mineralogist Friedrich Mohs. Minerals were tested for hardness by scrathing one material against another, and seeing which was the harder substance. Hardness refers to a minerals resistance to scratching. Then they were rated by which was more scratch resistant than the other.
The scale shows the hardness of minerals in a range of 1 to 10 where talc at 1 is the softest and diamond at 10 is the hardest. On this scale minerals with higher Mohs numbers can scratch minerals with lower Mohs numbers.
Here is a sample of some gemstones and where they rate on the Mohs Scale.
|This graph is taken from Wikipedia|
|This graph is taken from Wikipedia.|