Not being a man made material I think the mined mineral composition can vary, that, added to whatever else is in the packaging soup it's shipped in. That said,, anything with a high CEC can be charged and if it's used in a water system of less mineral content the mineral salts and carbonate buffers leach until equilibrium is reached. Once the stored charge of mineral ions has been depleted the remaining rock is inert.
Makes perfect sense Petrus.
haha! yes it does.
(now I'm looking for your posts to see what the pic will be next LOL)