Disclosed is a method for readily and inexpensively producing zeolite without using an organic structure-directing agent (organic SDA). Specifically disclosed is a method whereby a gel containing a silica source, an alumina source, an alkaline source and water is reacted with zeolite seed crystals, to produce a zeolite with the same kind of skeletal structure as the zeolite. The gel used is a gel of a composition whereby, when a zeolite is synthesized from this gel only, the synthesized zeolite comprises at least one of the kinds of composite building units of the target zeolite.

Disclosed is a method for readily and inexpensively producing zeolite without using an organic structure-directing agent (organic SDA). Specifically disclosed is a method whereby a gel containing a silica source, an alumina source, an alkaline source and water is reacted with zeolite seed crystals, to produce a zeolite with the same kind of skeletal structure as the zeolite. The gel used is a gel of a composition whereby, when a zeolite is synthesized from this gel only, the synthesized zeolite comprises at least one of the kinds of composite building units of the target zeolite.

The present invention relates to a full-Si molecular sieve, wherein the full-Si molecular sieve has a Q.sup.4/Q.sup.3 of (10-90):1 wherein Q.sup.4 is the peak strength at the chemical shift of 1122 ppm in the .sup.29Si NMR spectrum of the full-Si molecular sieve, expressed as the peak height relative to the base line; and Q.sup.3 is the peak strength at the chemical shift of 1032 ppm in the .sup.29Si NMR spectrum of the full-Si molecular sieve, expressed as the peak height relative to the base line.

A catalyst contains a metal oxide, and a molecular sieve, in a crystal form, having a topological pore structure. The metal oxide is centrally distributed on the surface of the molecular sieve. Grains of the molecular sieve are exposed to at least three families of crystal planes. The family of crystal plane with the largest pore size in topology is occupied by the metal oxide by no more than 30%, preferably no more than 20%, or no more than 10%.

A secondary growth procedure described herein is used to prepare finned zeolites. The finned zeolites possess properties that are distinctly unique compared to crystals of similar size lacking fins. The procedure is amenable to a wide range of zeolite crystal structures.