by Trevanion » 23 Jul 2022, 18:49
I would say it’s deposits of calcium carbonate rather than Silica, you tend to get silica more with Asian timbers such as Rosewoods and Teak, as Pete said, but with African timbers like Iroko and Wenge it tends to be calcium carbonate from experience.
Either way, it’ll ruin planer knives and bandsaw blades, you can pick it out of the grain with a sharp steel pick to make it finish better, very time consuming though.