If you mean Pokemon Ruby, Sapphire or Emeraldm, they can be traded with a hunter on an island halfway between Lilycove City and Mossdeep City. Pokemon Platinum shards are used to tutor moves to Pokemon on Route 212, Snowpoint City, and the Survival Area.
yellow shard and red shard and green shard
nothing
The green shard can be traded for a leaf stone if you talk to the Treasure Hunter on Route 124. Any shards can be traded in for an evolution stone. Yellow Shards = Thunderstones Blue Shards = Water Stones Red Shards = Fire Stones Green Shards = Leaf Stones However there are no shards that allow you to receive a Moon Stone.
The color shards you can find in Pokemon Platinum are Red, Blue, Green, and Yellow Shards.
They can't be bought. You can find them underwater, or attached to wild pokemon. Chinchou have yellow shards, Clamperl have blue shards, Relicanth have green shards and Corsola have red shards.
I believe you have to look for Red Gyarados for a Red Scale.
Red shards are found underwater.
Red Shards can be found randomly in Dive Spots (the dark patches on the sea, in case you didn't know) on things such as rocks, or crators.
In Platinum, the Red Shard and the other Shards are very valuable if you want to use 1 of the 3 Move Tutors there because you have to give them certain Shards for certain moves and the Red Shard is 1 of those many Shards so that would be a reason of why someone would want to get a Red Shard.
There are four shards in Pokemon Platinum- red, blue, green and yellow. They can all be found in the Underground.
You trade them for tms from a lady in pastoria
There is a move tutor west of pastoria city who will teach it to one of your Pokemon for 6 blue shards and 2 red shards ;)