… Granite, porphyry, basalt, sandstone and other monumental or building …
Explanatory notes
… 25.16 ‑ G ranite, porphyry, basalt, sandstone and other monu-mental or … and the presence of iron oxide or manganese oxide. Porphyry is a finely grained, slightly translucent variety … includes other hard igneous rocks (e.g., syenite, gneiss, trachyte, lava, diabase, diorite, phonolite), as well as …