Engraving materials: wood, some plastics, paper, bamboo, horns, thin leather (wallet), rubber stamp, photosensitive stamp, printing paper (mainly used for engraving, less material to cut), sponge paper, etc. Burnt material.
Can't engrave materials: metal (regardless of thickness), stone, ceramic, jewellery, jade, reflective material, transparent glass, ivory, colorless transparent material, part of white plastic (usually very smooth plastic is difficult to engrave)