what i think is that there should be a stone for every type, including the '???' type. (from the move in G/S/C, cant remember which one)
And eevee evolve accordingly
Fire stone = Flareon (From flare, meaning a burst of fire)
Water Stone = Vaporeon (From vapor, meaning a mist-like haze)
Leaf Stone = Floreon (From Flora, meaning plant-life)
Thunderstone = Jolteon (From jolt, meaning a sudden shock)
Sun stone = Espeon (From ESP, meaning Extra Senscory Perception)[ No more of that 'happiness' evolution]
Moon Stone = Umbreon (From Umb meaning dark somehow) [ see above]
Insect stone = Miteon (From mite, meaning a microscpic insect)
Ryu (japanese for dragon) stone = Drageon (from dragon, a sephentine mythical beast)
Power stone = Suplexeon (from suplex, a wrestling move)
Necro stone = spectreon (from spectre, a hateful ghost)
Dirty stone = terrateon (from terrato, the word for the crust of the earth)
Ice Stone = Crysteon (from crystal, a usualy cicle-shaped formation)
White stone = Eeveon ( from eevee, the basic pokemon, which means evolution)
Toxin stone = Poiseon (from poison, meaning... uh... poison.)
rare stone = Rubleon (from rubble, the remainder of crushed rocks)
Metal stone = Alloyeon (from alloy, which is a stronger form of a solid)
odd stone = unknowneon (from unknown, or to not know)