This work focuses on the erosion pattern morphology of the Indonesian excavating sponge Cliona albimarginata in three different calcareous substrates (Carrara marble, branches of the coral Acropora, and the umbo of the bivalve Hippopus). The experimental data demonstrate that the sponge produced galleries that followed the preferred orientation of fibrous aragonite crystals (Acropora), or the parallel lamination within the Hippopus shell. Conversely, the homogeneous granoblastic, mosaic texture of Carrara marble was etched without preferred directions. SEM analysis showed that pit size also varies between the three substrates in relation to the respective substrate porosity.