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The construction materials of the feudal castle of Pouzauges (Vendée, western France) mostly consists of biotite granite and hornfels, which come from the local Pouzauges granite massif, as demonstrated by the high barium content of the alkaline feldspar of the granite. However, a rare albite-rich white granite with white mica, columbite-tantalite and topaz has been used as ashlar, for the door and window framings, fireplaces, window seats and latrines. This granite comes from Les Châtelliers, at 9 km from Pouzauges, where old excavations are still visible. The observation of the monuments of the region shows that this granite was used as carved stone from the 12th to the early 20th century. Chosen for its low alterability and its aesthetic qualities, in particular its ivory white colour, this rock was used as ornamental stones for the openings, cornices and fireplaces of castles, and for columns, capitals, ogives and archivolts of churches. For ordinary walls, on the contrary, local rocks, either schists, granites or hornfels, were used. This study, among others, shows that the petrological examination of construction materials can make it possible to identify their origin, in particular when it comes to metamorphic or magmatic rocks, whose mineralogy is varied.