This is probably gonna take a while....... Just don't wanna go all the way back to petalburg woods when I'm already in the delta episode.
Here is your list:
Manectite (Route 110)
Aggronite (Rusturf Tunnel)
Steelixite (Granite Cave) I've put it here because you're likely to get it on your second visit to the area (after Norman) rather than backtrack after immediately picking up the bike
[email protected] (Route 118)
Your starters' stone (Route 120)
Absolite (Safari Zone)
Medichamite (Mt. Pyre - interior)
Banettite (Mt. Pyre - exterior)
Gyaradosite (Route 123)
Altarianite (Lilycove) I have this after Gyaradosite because I'm assuming you visit Mt. Pyre first, then take route 123 back to Slateport after Team Magma/Aqua prompt you to. There's no reason to go to Lilycove before / during the Mt. Pyre bit because of the nurse near Mt. Pyre...
Glalitite (Shoal Cave - low tide)
Slowbrownite (Shoal Cave - after getting Shell Bell)
Pinsirite (Route 124) You need Dive to get it and I figured you'd visit Shoal Cave before fighting Tate & Liza
Heracronite (Route 127) Technically, you can get this before Glalitite, but as far as the story progression goes, it's likely you won't have surfed down here yet
Sablenite (Sootopolis) Another Dive one
The others have been left out as they require the national dex to be obtained before you can get them.But if you want to their locations too,you can find them here.
Hope I helped!