A multi-color analysis of CCD frames and polarimetry for both dark patches and stars in the field of the globular cluster NGC 6624 is presented. Several of these patches have a wavelength behavior that is consistent with the existence of intra-cluster dust. The spatial distribution of these patches is not at random, rather, they appear distributed on a circular pattern some 2 parsecs in radius. Remarkably, the center of this structure, that seems to be a "bubble", is not far from the position of the X ray burster 1820-30. A possible connection between these objects might suggest the existence of an explosive event in the past.