Thread: Reasons I feel hones have to be sedimentary

The coticule site is metamorphic and not sedimentary. You wouldn't find garnets in a sedimentary rock. They form as a result of the heat and pressure applied to a sedimentary rock. Metamorphic rocks are therefor considered a separate class (Igneous is the third broad category). The escher stones were likewise metamorphically formed.

Jasper is just as likely as anything DEPENDING on what you're honing. Even leather has an effect on steel. Last year I photographed a Jade hone of Inuit origin at a museum in Sitka, Alaska. Jade is really soft but that's what they used.

The hardest steels are around 5.5 on the Mohs scale so anything above that such as garnet, quartz, corundum, carbide, diamonds, topaz, etc. will abrade steel. Hones don't necessarily have to be sedimentary. Even the slate hones of Wales are slate which is metamorphosed shale - much harder than shale.

My two cents!