NOVELTY - A crystalline titanium silicate molecular sieve having a formula representing mole ratios of specified oxides, is new.    USE - The sieve is for use in a titanium silicate molecular sieve composition, and for an adsorbent used in an adsorber for use in adsorptive fluid separation process comprising a pressure swing separation process and rapid cycle pressure swing separation process (claimed), e.g. for separating methane from air. It is for use in high temperature catalytic processes.    ADVANTAGE - The crystalline titanium silicate molecular sieve is stable, both chemically and thermally and has stable physical properties, such as pore size and adsorptive characteristics, even with varying ambient conditions such as temperature. It is highly adsorptive toward molecules of a particular size range, which varies from greater than or equal to 2 up to approximately 5, preferably 3-4.5 Angstrom in diameter, and is non-adsorptive to molecules having effective diameters larger than 5 Angstrom in critical diameter; has the ability to control pore size through a variety of mechanisms; and has a high degree of thermal stability at greater than or equal to 200, preferably greater than or equal to 450degreesC.    DETAILED DESCRIPTION - A crystalline titanium silicate molecular sieve having a formula representing mole ratios of oxides of n M1O:TiO2:y SiO2:zH2O:wX, is new.    M1=metal cation(s);    n=1-2;    y=1-10;    z=0-100;    X=halide anion other than F, or a combination of anions excluding F;and    w=greater than 0.    INDEPENDENT CLAIMS are included for:    (1) a process of preparing the titanium silicate molecular sieve;    (2) a process for adjusting the pore size of the titanium silicate molecular sieve comprising performing ion exchange on the titanium silicate molecular sieve to produce an ion-exchanged titanium silicate molecular sieve having a formula representing mole ratios of oxides of n M2O:TiO2:y SiO2:zH2O:wX;    (3) a titanium silicate molecular sieve composition comprising titanium silicate molecular sieve; and greater than 0-less than 100 wt.% of an additional material(s); and    (4) an adsorptive fluid separation process comprising providing the titanium silicate molecular sieve; and contacting the titanium silicate molecular sieve with a feed fluid mixture comprising two components to produce a product fluid(s) enriched in the first component relative to the second component using an adsorption process.    M2=metal cation(s).