Trim fat from chops. In a small bowl, combine rosemary, salt, and pepper. Sprinkle evenly over chops; rub in with your fingers. In a large nonstick skillet, heat oil over medium heat. Add lamb chops. Cook for 8 to 10 minutes or until lamb is desired doneness (145°F for medium-rare or 160°F for medium) or pork is slightly pink in the center (160°F), turning once halfway through cooking. Remove chops from skillet. Cover with foil and keep warm.
In the same skillet, combine grapes, vinegar, and water. Cook and stir just until boiling; reduce heat. Cook and stir for 1 to 2 minutes more or until grapes are softened but still hold their shape. Serve grape mixture over chops. If desired, sprinkle with mint.