A method for separating fluids, comprising: exposing an input fluid stream comprising a first fluid component and a second fluid component to a membrane comprising particles of crystalline zeolite ITQ-55 to form a permeate product fluid stream and a rejection product fluid stream, a molar ratio of the first fluid component to the second fluid component in the permeate product fluid stream being greater than a molar ratio of the first fluid component to the second fluid component in the input fluid stream, a molar ratio of the first fluid component to the second fluid component in the rejection product fluid stream being less than a molar ratio of the first fluid component to the second fluid component in the input fluid stream, wherein the zeolite ITQ-55 has a framework of tetrahedral atoms connected by bridging atoms, wherein the tetrahedral atom is defined by connecting the nearest T atoms in the manner described in the following Table: ITQ-55 tetrahedral atom interconnections T atom Connected to: T1 T6, T7, T55, T73 T2 T3, T5, T9, T56 T3 T2, T7, T21, T27 T4 T8, T9, T58, T73 T5 T2, T8, T52, T59 T6 T1, T8, T53, T60 T7 T1, T3, T50, T61 T8 T4, T5, T6, T51 T9 T2, T4, T21, T63 T10 T15, T16, T64, T74 T11 T12, T14, T18, T65 T12 T11, T16, T30, T36 T13 T17, T18, T67, T74 T14 T11, T17, T43, T68 T15 T10, T17, T44, T69 T16 T10, T12, T41, T70 T17 T13, T14, T15, T42 T18 T11, T13, T30, T72 T19 T24, T25, T37, T73 T20 T21, T23, T27, T38 T21 T3, T9, T20, T25 T22 T26, T27, T40, T73 T23 T20, T26, T41, T70 T24 T19, T26, T42, T71 T25 T19, T21, T43, T68 T26 T22, T23, T24, T69 T27 T3, T20, T22, T45 T28 T33, T34, T46, T74 T29 T30, T32, T36, T47 T30 T12, T18, T29, T34 T31 T35, T36, T49, T74 T32 T29, T35, T50, T61 T33 T28, T35, T51, T62 T34 T28, T30, T52, T59 T35 T31, T32, T33, T60 T36 T12, T29, T31, T54 T37 T19, T42, T43, T75 T38 T20, T39, T41, T45 T39 T38, T43, T57, T63 T40 T22, T44, T45, T75 T41 T16, T23, T38, T44 T42 T17, T24, T37, T44 T43 T14, T25, T37, T39 T44 T15, T40, T41, T42 T45 T27, T38, T40, T57 T46 T28, T51, T52, T76 T47 T29, T48, T50, T54 T48 T47, T52, T66, T72 T49 T31, T53, T54, T76 T50 T7, T32, T47, T53 T51 T8, T33, T46, T53 T52 T5, T34, T46, T48 T53 T6, T49, T50, T51 T54 T36, T47, T49, T66 T55 T1, T60, T61, T75 T56 T2, T57, T59, T63 T57 T39, T45, T56, T61 T58 T4, T62, T63, T75 T59 T5, T34, T56, T62 T60 T6, T35, T55, T62 T61 T7, T32, T55, T57 T62 T33, T58, T59, T60 T63 T9, T39, T56, T58 T64 T10, T69, T70, T76 T65 T11, T66, T68, T72 T66 T48, T54, T65, T70 T67 T13, T71, T72, T76 T68 T14, T25, T65, T71 T69 T15, T26, T64, T71 T70 T16, T23, T64, T66 T71 T24, T67, T68, T69 T72 T18, T48, T65, T67 T73 T1, T4, T19, T22 T74 T10, T13, T28, T31 T75 T37, T40, T55, T58 T76 T46, T49, T64, T67. exposing an input fluid stream comprising a first fluid component and a second fluid component to a membrane comprising particles of crystalline zeolite ITQ-55 to form a permeate product fluid stream and a rejection product fluid stream, a molar ratio of the first fluid component to the second fluid component in the permeate product fluid stream being greater than a molar ratio of the first fluid component to the second fluid component in the input fluid stream, a molar ratio of the first fluid component to the second fluid component in the rejection product fluid stream being less than a molar ratio of the first fluid component to the second fluid component in the input fluid stream, wherein the zeolite ITQ-55 has a framework of tetrahedral atoms connected by bridging atoms, wherein the tetrahedral atom is defined by connecting the nearest T atoms in the manner described in the following Table: ITQ-55 tetrahedral atom interconnections T atom Connected to: T1 T6, T7, T55, T73 T2 T3, T5, T9, T56 T3 T2, T7, T21, T27 T4 T8, T9, T58, T73 T5 T2, T8, T52, T59 T6 T1, T8, T53, T60 T7 T1, T3, T50, T61 T8 T4, T5, T6, T51 T9 T2, T4, T21, T63 T10 T15, T16, T64, T74 T11 T12, T14, T18, T65 T12 T11, T16, T30, T36 T13 T17, T18, T67, T74 T14 T11, T17, T43, T68 T15 T10, T17, T44, T69 T16 T10, T12, T41, T70 T17 T13, T14, T15, T42 T18 T11, T13, T30, T72 T19 T24, T25, T37, T73 T20 T21, T23, T27, T38 T21 T3, T9, T20, T25 T22 T26, T27, T40, T73 T23 T20, T26, T41, T70 T24 T19, T26, T42, T71 T25 T19, T21, T43, T68 T26 T22, T23, T24, T69 T27 T3, T20, T22, T45 T28 T33, T34, T46, T74 T29 T30, T32, T36, T47 T30 T12, T18, T29, T34 T31 T35, T36, T49, T74 T32 T29, T35, T50, T61 T33 T28, T35, T51, T62 T34 T28, T30, T52, T59 T35 T31, T32, T33, T60 T36 T12, T29, T31, T54 T37 T19, T42, T43, T75 T38 T20, T39, T41, T45 T39 T38, T43, T57, T63 T40 T22, T44, T45, T75 T41 T16, T23, T38, T44 T42 T17, T24, T37, T44 T43 T14, T25, T37, T39 T44 T15, T40, T41, T42 T45 T27, T38, T40, T57 T46 T28, T51, T52, T76 T47 T29, T48, T50, T54 T48 T47, T52, T66, T72 T49 T31, T53, T54, T76 T50 T7, T32, T47, T53 T51 T8, T33, T46, T53 T52 T5, T34, T46, T48 T53 T6, T49, T50, T51 T54 T36, T47, T49, T66 T55 T1, T60, T61, T75 T56 T2, T57, T59, T63 T57 T39, T45, T56, T61 T58 T4, T62, T63, T75 T59 T5, T34, T56, T62 T60 T6, T35, T55, T62 T61 T7, T32, T55, T57 T62 T33, T58, T59, T60 T63 T9, T39, T56, T58 T64 T10, T69, T70, T76 T65 T11, T66, T68, T72 T66 T48, T54, T65, T70 T67 T13, T71, T72, T76 T68 T14, T25, T65, T71 T69 T15, T26, T64, T71 T70 T16, T23, T64, T66 T71 T24, T67, T68, T69 T72 T18, T48, T65, T67 T73 T1, T4, T19, T22 T74 T10, T13, T28, T31 T75 T37, T40, T55, T58 T76 T46, T49, T64, T67.