There is a house on the water to the left of mossdeep and he will ask for shards and he will give you stones.
Yellow shard: thunderstone
Green shard: leaf stone
red shard: fire stone
blue shard: water stone
you can trade shards for stones in hunters house. His house is southwest of mossdeep.
you get stones for shards from some persons house west of mossdeep
In HG/SS you trade Shards for Berries. Trade with Jugglers in Violet City and Fuchsia City.
You first have to find them when you use the explorer kit and mine down there for shards.
find the guy who collects shards and trade shards for stones
near pastoria
if you have to trade shards then trade Pokemon with people eqiupe it to a Pokemon your trading and theres shard trading make sure the other trainer has equiped a shard to the tradable Pokemon
In violet city
You don't trade the shards for stones, you trade them for berries. You trade them with the man standing outside the Pokemon Centre in Violet City, and you'll get 3 berries from a specific set depending on the colour of your shard
you can trade them for moves i prefer to go to snowpoint city to trade them but there are other locations now speak to the hiker at snowpoint city (he lives at the house right from the temple) and ask him for the move you want from the list and trade the shards for the move
You can't. You can only trade it for TMs,10 red shards-sunny day,blue-rain dance,green-hail,yellow-sandstorm.
you can trade them for berry's with the guy in violet city