You can't. If you want Umbreon, you need to level up eevee at max happiness during the NIGHT. If it's daytime, you will get an Espeon.
you can use a fire stone water stone and thunder stone on an evee fire stone is flareon thunder stone is jolteon and water stone is vaporeon
use a leaf stone
For ruby and sapphire and emerald and for all 386 Pokemon, pikachu+thunderstone=raichu, evee+thunderstone=jolteon, evee and waterstone=vaporeon, evee+fire stone=flareon, clefairy+moon stone=clefable, jigglypuff+moon stone=wigglytuff, nidorino and nidorina+moon stone= nidoking and nidoqueen, skitty+moon stone=delcatty, vulpix+fire stone=ninetales, exeggcute+leafstone=exeggutor, gloom+sun stone or leaf stone= bellossom or vileplume, weepinbell+leafstone=victreebel, lombre+waterstone=ludicolo, shellder+water stone= cloyster, staryu+waterstone=starmie, poliwhirl+waterstone=poliwrath i think that's it.
Use a water stone.
evee can evole into three things in firered and leafgreen. it can evolve into flareon if you use the fire stone, jolteon if you use the thunder stone, or vaporeon if you use the water stone.
you can use the fire stone on vulpix,growlithe,evee,and other Pokemon
NO to get umbreon you make eevee super friendly and then level at night or use moon shard (not on d/p)
Well, there are seven evolutions. FLAREON Use fire stone on evee. VAPOREON Use water stone on evee. JOLTEON Use thunder stone on evee. UMBREON Gain complete friendship and level up evee during the night. ESPEON Gain complete friendship and level up evee during the day. LEAFEON/GLACEON I don't belive there is a way. You probably have to trade.
Evee, Pikachu.
the stones are water stone fire stone and thunder stone
The moon stone like other Pokemon games are used for evolving pokemon such as nidoran, nidorino, jigglypuff, Evee, ect some more.
bulbasaur 3:)