Fossils.
in rustboro city
fOSSilesied fossils and diamonds and ruby
I don't know go to a different website
No, not all fossils can be found in Omega Ruby or Alpha Sapphire however the fossils that can be found would include the Dome Fossil also known as the Kabuto fossil, Plume Fossil which is the Archen fossil and Armor Fossil which is also the Shieldon fossil can be found in Omega Ruby, the Skull Fossil also known as the Cranidos fossil and Cover Fossil (also known as the Tirtouga fossil) can be found in Alpha Sapphire while the Old Amber Fossil which is the Aerodactyl fossil can be found in both Omega Ruby and Alpha Sapphire.
Talk to the scientist in the southeastern most of the 2nd floor.
you don't
no
In Sapphire you only can get one of the two fossils found in the desert. If you have a trade buddy you could trade over the fossil Pokemon from Fire Red/Leaf Green and the second one from Ruby/Sapphire. In emerald you get both Hoenn Fossils, but at different points in the game.
A ruby is a ruby; a diamond is a diamond. They are different gemstones. Both occur in nature.
I have Pokemon Sapphire, but it's the same thing in both games. There are two fossils, one is the root fossil and one is the claw fossil. The root fossil will get you a Lileep (which then evolves into a Cradily at lvl40) and the claw fossil will get you an Anorith (which also evolves at lvl40 to give you an Armaldo). Hope that helps!!
Both! The fossils within limestone holding caves are of long-extinct animals, but they had still evolved to the species preserved as fossils.