Ferrierite ore is activated for normal paraffin conversion by exchanging with the ammonium ion, heating in air at a temperature from about 775.degree. to about 1000.degree. F and exchanging again with the ammonium ion. Activation of ammonium ferrierite for conversion of branched paraffins is accomplished (1) by treatment with HF or (2) by heating in steam at a temperature within the above range, followed by exchange with ammonium ion. Ferrierite ore per se may be treated with HF, but to complete activation for conversion of branched paraffins, the HF treated ore must be exchanged with the ammonium ion.