Harmotome, associated with analcime, is described from andesite dykes at Rehia and Maungarahu in the Tokatoka district, New Zealand. The Maungarahu harmotome has the composition: (Na_1·03K_0·23)(Ba_1·54Ca_0·18)Al_4·66Si_11·31 12·39 H₂O; physical properties: α 1·498, β 1·503, γ 1·506, 2V_γ 75–82° β:[001] 28° D 2·378; and cell constants: a 9· 906±0·006, b 14·119 ±0·003, c 8·712±0·007 Å, β 124° 57′ ± 3′. The harmotome is Ba-poor, and 2 Na⁺ has substituted for Ba²⁺ on a valency basis. Analcime associated with the Maungarahu harmotome has chemical composition: (Na_15·16 K_0·03Ca_0·09)Al_15·52Si_32·47 15·93 H₂O and physical properties: n = 1·483, D = 2·257, a = 13·708 Å. The zeolites are believed to have crystallized from Na and Ba-rich alkaline solutions at approximately 200°C The source of the Ba is baryte concretions in adjacent limestones.