Research on Different Pyrites in Late Permian Coal of Sichuan P...答:The granular,pellet, framboid-like,rod,fibre,bandary,milk colloidal and smooth,level,uneven etc. structure had been observed on the surface of pyrite crystal or fracture by STM. On the crystal face,oxidative corrosion pit ( relics) are often observed. Generally,on fine granular surface of ...