The invention relates to a composite formed of a zeolite (such as ZSM-5 zeolite, .beta.-zeolite and silicalite) deposited on a rigid support, wherein the rigid support comprises silicon carbide (SiC) with a specific surface area BET of at least 5 m.sup.2/g. Preferably, the support is a .beta.-SiC foam with a specific area of between 10 and 500 m.sup.2/g. This composite may be used as a catalyst and/or a catalyst support for chemical reactions in a gas or liquid medium. For example materials of the present invention are useful for example, in connection with cracking, acylation, alkylation and/or isomerization of hydrocarbons.