The aim of this contribution is to focus on the skin’s colour, a "mere" morphological characteristic, which has influenced and still influences the corruption of inter-human relations and, consequently, the formative paths of humanisation. Inside the multifaceted galaxies of racism, colourism - as the obsessive attention to the nuances of skin is defined - appears as both cause and effect of old and new discriminations. Moreover, colourism acts in a treacherous and underhand way, provoking an adhesion to the marginalisation 'system' even involving the victims themselves as they accept a 'white-centric' hierarchy and priority. In order to oppose and prevent colourism in a formative way, one can only summon up to all abilities of the whole human being. Such abilities also find in reciprocal vulnerabilities a basis for respecting common humanity.