In this paper we study the asymptotic theory for quadratic variation of a harmonizable fractional -stable process. We show a law of large numbers with a non-ergodic limit and obtain weak convergence towards a L\évy-driven Rosenblatt random variable when the Hurst parameter satisfies and . This result complements the asymptotic theory for fractional stable processes investigated in e.g. \cite{BHP19,BLP17,BP17,BPT20,LP18,MOP20}.
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