The Silent Shard appears to be pitch-black boot soles that can be placed on the bottom of shoes to give them the ability to make no noise while moving, no matter the substance that is being moved through. You also have advantage on Dexterity (Stealth) checks that rely on moving silently. If placed on bare feet, it will do 2d12 necrotic damage and fuzes to the feet. This damage can't be recovered until after The Silent Shard is removed by the command word.