Curlew has been around since 1979, and its recorded legacy, if nothing else, reveals that being persistently iconoclastic is not easy. Mercury (Cuneiform) is the band’s ninth album and quite possibly its best. Curlew’s music has awkward edges, and Dean Granros’ raw guitar explores the tensions between jazz and rock. The group’s wide-ranging eclecticism (avant-garde flourishes and ambient soirees) offers many possibilities that are teased out and examined in numbers like “Funny Money” and “Late Date/There Is.” The extreme indigestibility of “Leaven,” over a diving backbeat, with overdriven guitar and lumpy rock rhythms, is typical of the band’s approach and is the musical equivalent of jumping into the cold plunge pool after a sauna. You don’t want to do it too often, but when you do, it gives you a greater appreciation of the everyday. Featuring saxophonist George Cartwright, whose edgy sound is central to Curlew’s musical personality, the band’s idiosyncratic take may be something of an acquired taste, but it’s one well worth acquiring.