Kevin French
My wife wants to mine Herkimer Diamonds on our return from dropping her daughter off at college in Guelph Canada.

I've done a bit of reading and the consensus is to take several Cold Chisels to use as wedges and a file to keep them sharp.

In prep, I have cleaned and sharpened them on my grinder but I'm looking for the right file for the field work next week.

Throwing my vast collection of odd files at this I've found that a Mill Bastard file seem to work the best. Can someone confirm this or suggest another type of file.