By Chris Richards, The Washington Post “My musical quest (is) to get more and more purity into the music.” That’s something Tom Petty told me over the telephone once. Years later, I wonder if he died — on Monday in California at age 66 — pushing that boulder uphill. Because it was always the impurity of Petty’s music that made it feel so sublime. Even back in ’70s, when he was just a blond smirk in a black leather jacket, Petty’s brand of Americana was already exuding its own mood, its own smell.