This one is annoying to get.
Shard - Drops from Rocks Worms in 2-2. Drops from Hammer Scale Miners in 2-1/2-2.
Chunk - Found as treasure in 2-2 and Rare drops from Rock Worms in 2-2.
Pure - Show Scrirvir the Dragon Bone Smasher in Pure White World Tendency in 2-2. Very Rare drop from Rock Worms in 2-2.
Information gotten fromhttp://demonssouls.wikidot.com/upgrade-crushing