Yes, the agate was heat treated @350-400. The stone came from mid-state within a couple miles of the Columbia river where a mining company mines Diatomaceous Earth. The agate is in a layer between common opal (which is knappable) but there was only a few areas you could find it, and about 8-10yrs back they backfilled that pit....so as far as I know I am the only knapper to have this piticular stone....kinda a bummer.
Last time I was there all the stone was crap that could not be knapped.