This thing is far beyond all my expectations! I'd never used a stone pick before purchasing this one, and the picks I use get a "hearty pounding" and wear off quite quickly. This agate beauty not only takes heavy licking without as much as a scratch, but also sticks to the fingers surprisingly well.
The sound of strings plucked with stone may seem a bit off on the "muffled" side, but I've found it a motivation to perfect my articulation further, rather than a drawback.
I've been relying on a granite fretboard on a seven-string for over a year now for stability and haven't been let down; now I have an complement of an agate pick for smoothness, longevity, and sheer beauty.
Compared to American prices (haven't found a European producer so far) these are for free! I received the pick in about a week after the order was processed and it came all neatly packed'n'wrapped.
I'm definitely coming back for more!
Cheers from Poland!