The Hardness Scale of Science Fiction

Thursday, December 23rd, 2010

When I was a kid, I collected rocks.   One of the rock-related items I bought was a sheet of cardboard labeled Mohs Scale of Hardness.   Talc is a one, while diamond is a ten.   Tooth enamel is apparently a five.   My card didn’t have a diamond on it when I bought it, but an encouraging […]

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