I want to start working on a competitive Ice Monotype team and for one of my mons I need an Icy Rock. To clarify, I mean Icy Rock the item, not the rock you use to evolve Eevee into Glaceon.
I looked it up and I found that it is possible to get it somehow in the Underground. The website I used showed a chart of the items you can get from the Underground. Thing is, I don't understand what most of it means. Plus the weather duration rocks aren't even called the same thing as normally(example, the Icy Rock is listed as the Icy Stone, and the Damp Rock is listed as the Damp Stone). This is the website.
Could anyone explain the most simple way to obtain the Ice Rock(or any other weather rocks) in Gen 4? I know the Pokewalker is kinda an option but I don't have that.