these are a couple stones I got from an ex-barber they both have some kind of marking on them. I'm hopeing somebody can identify them, or atleast know more about them than i do

this first one is an olive drab color marked kansas school of barbering, and it's not very course
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the next one is grey and says a product by carborundum N0. 159 sic, this one is a bit more course than the first

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any information would be appreciated.