Explanatory notes
… square) shape (+). - Granite : 2516.11 - - Crude or roughly trimmed 2516.12 - - Merely cut, by sawing … of these three substances and the presence of iron oxide or manganese oxide. Porphyry is a finely grained, … blackish, very compact and extremely hard. The heading also includes other hard igneous rocks (e.g., syenite, gneiss, …