This paper presents the hydrochloric attack of serpentinites. Romanian serpentinites are part of the Danubian crystalline complex. These serpentinites contain mineral serpentine (magnesium silicate) and a small amount of other minerals along with calcium, iron, aluminium, nickel, cobalt, chrome and manganese. For processing, the serpentinite was attacked by hydrochloric acid from two provinces (p.a. and residual hydrochloric acid), using different experimental conditions: acid concentrations between 15-23 per cent HCl, the temperature range of 70-90 degrees C, with stoichiometric ratio between reactants and with acid excess, the extraction time being up to 180 min. In optimum conditions, the magnesium extraction is almost total (99.5 per cent). A well-balanced processing of these serpentinites looks for both the silica residue utilization and the chloride solutions, in order to separate the prevalent magnesium as well as the valuable microcomponents--nickel and cobalt.