In game they are found: Crystals in Build mode, Rocks and Pipes in Deco and Lawn Ornaments.
New versions (yet again, now in a combined package) uploaded, please redownload. Seems they didn't like to be separated - maybe something conflicted. Now all 4 show up under Build/Rocks and in Edit Town.
Now (20.02.2012) the pipes also are updated and show in world editor in game, under landmarks. All six parts are now there. And under Misc Deco / Lawn Ornaments. I made a combined package of them to. If you downloaded the previous single files, delete them and place this new pipes package in CAW framework and in Mods/Packages.