<p>The main evidence of exploitation of “alternative” volcanic pozzolans other than <i>pulvis puteolanus</i> from the Gulf of Pozzuoli volcanic districts and <i>harenae fossiciae</i> from the Colli Albani volcanic district. *Legend: TPL-OM = Transmitted Polarized Light-Optical Microscopy; XRD = X-Ray Diffraction; SEM-EDS = Scanning Electron Microscopy coupled with Energy-Dispersive Spectroscopy; XRF = X-Ray Fluorescence; AES = Atomic Emission Spectrometry; AAS = Atomic Absorption Spectrometry.</p>

The main evidence of exploitation of “alternative” volcanic pozzolans other than pulvis puteolanus from the Gulf of Pozzuoli volcanic districts and harenae fossiciae from the Colli Albani volcanic district. *Legend: TPL-OM = Transmitted Polarized Light-Optical Microscopy; XRD = X-Ray Diffraction; SEM-EDS = Scanning Electron Microscopy coupled with Energy-Dispersive Spectroscopy; XRF = X-Ray Fluorescence; AES = Atomic Emission Spectrometry; AAS = Atomic Absorption Spectrometry.