Best known as background singers for Kelly Clarkson, Jill Pickering and Kate Rapier have also distinguished themselves as a singer/songwriter duo of real craft and charm. The pair’s fourth album, Heart of Stone, deserves wider recognition thanks to its sensitive, well-rendered tunes and sterling vocal harmonies. Jillandkate temper romance with realism, celebrating new love even as they aim to put aside bad memories. A bittersweet vein runs through many of these songs, heard in the wounded regret of “Burn It Down” and the title number. “Breakdown”—a folk-pop piece reminiscent of The Indigo Girls—suggests there’s life beyond heartache. When Jillandkate show their more upbeat side, they capture the delirious joy of infatuation (“I Come Alive,” “Together Baby”), as well as the pleasures of putting down an egotistical ex (“Skinny Jeans”). The album closer, “Life and Breath and Everything,” is a quietly fervent ode to the Creator. Heart of Stone’s production emphasizes acoustic sounds with a touch of country-pop sleekness.