Ve must remember in der Science, all data is of importance. Now we know:-

The Mohs Hardness Scale is shown below
Diamond 10
UFO 10.5
Corundum (Ruby and Sapphire) 9
Topaz 8
Quartz 7
Orthoclase (Feldspar) 6
Apatite 5
Wind Farm Propeller 5.5
Fluorite 4
Calcite 3
Gypsum 2
Talc 1

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Any fool can ask a profound question that takes a wise man decades to answer.