In the Granite Cave at Dewford town. It is not too hard to find it there.
Chat with our AI personalities
go underground and look for them
Moon Stone can be found in Meteor Falls, you must get HM07 (Waterfall) before you can get it. :)
Abandoned ship, Rm. 2, while trying to get the Scanner after diving.
Water Stone...Well... If I remember correctly, there's a guy who's willing to trade a water stone for a Blue Shard. Oh! And you can find one on the Abandoned Ship.
Lucario isn't in Sapphire,Sapphire is a Hoenn pokemon,Lucario is a sinnoh pokemon.