Hello gentleman, as the title states I am in need of a possible stone identification please? This stone is very fine. It left a nice keen edge. It is small and it came with a razor which was junk so I just took the stone for $10. In person the color looks blue Grey but don't quote me I have no idea. Thank you

Measurements are 1 1/8" wide 5 7/8" long and 5/8" thick
Surface the way I found it
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Lapped flat dry
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Wet
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Light slurry from dmt 325
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