"robo hippy" wrote in message
oups.com...
The biggest difference in dulling seems to be the woods. The prettiest
myrtle wood comes from the Oregon and north California coast. It can
dull the tools more quickly than other woods. My theory on that is
that it has a higher silica content than most other woods because
growing on the coast, it sucks up a lot of micro particles of silica/
sand.

Seems unlikely the tree could transport particulates, though soluble silica
compounds may be metabolized into less soluble or insoluble types. One
common mineral stain in our local woods is calcium oxalate, the stuff of the
common kidney stone. It will dull tools, that's for sure.

I'm sure others have noticed that trees which retain branches for a long
time often have greenish stain in the convoluted grain on the ground side of
the branches, where a less-soluble compound would naturally slow along with
the reduced flow to the crown. I rather suspect this is the same calcium
oxalate. Our common eastern white cedar is one which has both green and the
dulling effect. Proportionate, I don't know. Never paid that much
attention. I sharpen when the tool is no longer cutting cleanly.