Coveted Jewel is a rare Artifact card from March of the Machine Commander (MOC), collector number 353. Current market price: $0.38, TCGplayer market prices via Scryfall.
When this artifact enters, draw three cards. {T}: Add three mana of any one color. Whenever one or more creatures an opponent controls attack you and aren't blocked, that player draws three cards and gains control of this artifact. Untap it.