New zeolite SSZ-23 and xylene isomerization therewith

A method for preparing a zeolite having a mole ratio of an oxide selected from silicon oxide, germanium oxide and mixtures thereof to an oxide selected from aluminum oxide, gallium oxide, iron oxide, boron oxide and mixtures thereof greater than about 50:1, and having the X-ray diffraction lines of Table 1, comprising:

• (a) preparing an aqueous mixture containing sources of an adamantane quaternary ammonium ion, an oxide selected from aluminum oxide, gallium oxide, iron oxide, boron oxide and mixtures thereof, and an oxide selected from silicon oxide, germanium oxide, and mixtures thereof;
• (b) maintaining the mixture at a temperature of at least 140.degree. C. until the crystals of said zeolite form;
• and
• (c) recovering said crystals.