Shard of Broken Glass is a common Artifact — Equipment card from Shadows over Innistrad (SOI), collector number 262. Current market price: $0.13 (foil $0.33), TCGplayer market prices via Scryfall.
Equipped creature gets +1/+0. Whenever equipped creature attacks, you may mill two cards. Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)