The Mesoproterozoic metagranites and metasediments of the Mt. Painter Inlier, Arkaroola, contain a variety of unusual titanite-bearing veins: a) megacryst diopside titanite (10%, up to 40 cm) pegmatites, which are WNW-ESE striking and up to 5 m in thickness. They contain minor amounts of quartz, hematite, calcite and apatite. Titanite crystals do not show reaction zones with diopside, which are partly hydrothermally altered to actinolite; b) scapolite (marialite) quartz actinolite titanite (7%, up to 1 cm) veins with epidote (secondary), biotite, zircon and magnetite as accessories minerals; c) Kfeldspar calcite diopside titanite (5%, up to 1 cm) pegmatites, which are asymmetrical zoned: the center part contains mainly Kfeldspar and quartz with miaroles, whereas one rim contains titanite crystals and the opposite rim contains actinolite crystals. Fluid inclusions (fi) are abundant in diopside, titanite, quartz, calcite and apatite. Inclusions in titanite and diopside are investigated optically, with ramanspectroscopy and XRF spectroscopy using an electron microprobe. Titanite has similar inclusions in all three rock types and contains trails of dark inclusions with a strong re-equilibration texture. A brine and a vapour bubble are observed in some of these inclusions. Beside monazite and zircon, titanite contains a variety of sporadic exotic minerals, such as baddeleyite, uraninite, thorianite and fergusonite. Accessory minerals in diopside are among others: baryt, pyrit, scheelite and wakefieldit. Inclusions in quartz are investigated additionally with microthermometry. Four types of fluid inclusions are identified: 1) aqueous, irregular elongated fi with sizes up to 75 m and either low or high salinity of unknown composition. Homogenisation temperatures in low saline fi reaches values up to 350°C; 2) CO2 rich secondary inclusions with negative crystal forms. The density of these fi vary between 0.956 and 0.584 g/cc; 3) highly complex fi with different solid phases (salts, calcite, hematite). Vapour and liquid homogenize around 120°C, whereas salt and calcite crystals dissolve at higher temperatures, up to 580°C; 4) homogenous, aqueous fi (secondary) with diameters smaller than 5 micron. Electron-microprobe analyses of titanite show a zonation caused by different enrichments in LREE (mainly Nd), Y and Nb. Diopside is relatively enriched in Fe (i.e. salite) wheras REE are not detected. Monazites in titanite and quartz are enriched in Ce and contain considerable amounts of Th.