You must evolve the Cacnea which is found on route 111 and evolve at level 32. You need the Go-Goggles to get through the sandstorm that is always going in the Desert on Route 111. You get those in Lavaridge.
Sadly, you can't catch Groundon is the Sapphire Version, however you can in the Ruby version, you will find him in the same place you find Kyorge in the sapphire version.
No Cacturne cannot learn mega kick. Here is Cacturne's move set:StartFRLGRevengeStartPoison StingStartLeerStartAbsorbStartGrowth5Absorb9Growth13Leech Seed17Sand-Attack21Pin Missile25Ingrain29Faint Attack35Spikes41Needle Arm47Cotton Spore53Sandstorm59FRLGDestiny Bond
you can find minum in sapphire in lots of places
in the ground
somewere in the 30's and it evolves into cacturne and cacturne is a amazing grass type and I recomend it completely (make it learn needle arm)
Murkow can't be found in the wild in Sapphire version. You have to trade from Fire Red or Colosseum.
Route 115
Diglet cannot be found in sapphire only if you trade from other version.
you cant find shiny stone in Sapphire only in pearl nooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo you cant nooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo you cant
Catch a cacnea in the desert then train it to level 33 and it will become a cacturne.
You must trade from LeafGreen version.
In the waters of the safari zone