Rowan's Eyes of Charming were a lens made of crystal that allowed the wearer to cast the spell Charm Person 3 times per day. This could be done if the target (who must be within 30 feet, and they must be able to see each other), failed a DC 13 WIS saving throw. They had an inscription inside, the name of their previous owner, Verona. As of Episode 301, they also gave Rowan advantage on Persuasion rolls.
Rowan Grey found the Eyes in the Impound room of Grull, along with the rest of their effects. The inscription inside read "Verona", hinting at the Eyes' previous owner.