That sounds very similar, if not identical. Isn't slate a metamorphic rock derived from shale? The primary agricultural use of permatill here in North Carolina is to break up dense clay soil in flowerbeds. Secondary use is to discourage burrowing pine voles (Microtus). Because it is used so frequently, I can buy it at local garden centers. 50 lb bag costs approx $12 or 13. On Tue, Oct 27, 2015 at 3:12 PM, Cynthia Mueller <cynthiasbulbs@hotmail.com> wrote: > Nick, I'll look for this product. Something relatively new is being > promoted in Texas to condition hardened flower beds - it's expanded shale, > resembling small grey beads and may be inert. > > Cynthia W Mueller > >