We report the presence of large aggregates (diameter > 1 cm) of diaspore related to the serpentinization
of the Sierra Alpujata massif of the Ronda peridotites (Betic Cordilleras, southern Spain). The diaspore is
found in two different but related settings: in narrow metasomatic rims pervading the peridotites from
steeply dipping tension joints and in the blackwall zone developed along the normal fault that separates
the peridotites from the overlying metamorphic cover. The systematic association of diaspore with chlorite
points to very low temperature conditions (T < 100 ºC) for diaspore formation