Lava is much used for paving-stones in the neighborhood of volcanic districts, where pozzolana (for cement) and pumice stone are also important.
The mineral wealth of the Cyclades has hitherto been much neglected; iron ore is exported from Seriphos, manganese and sulphur from Melos, and volcanic cement (pozzolana) from Santorin.
According to modern physicians it is impossible to live many days in the caves of pozzolana in which many of the catacombs are excavated."
1 The pozzolana is the material required for building purposes, for admixture with mortar; and the sandpits are naturally excavated in the stratum which supplies it.
It exported iron from Elba, mosaics, pottery, manufactured locally with earth from Ischia (which was in considerable demand until 1883), sulphur (which indeed was extracted in the neighbourhood until the 18th century), probably alum (which is still worked), perfumes, pozzolana earth (taking its name from the place), cretaceous earth for mixing with grain (alica) from the Leucogaean hills, glass cups engraved with views of Puteoli, mineral dyes (the blue invented.