Graphite /ˈɡraefaɪt/ , ˈɡræfaɪt archaically referred to As, plumbago is a crystalline form of, carbon a, semimetal a native element, mineral and one of the allotropes of. carbonn milling, the incoming graphite products and concentrates can be ground before being classified (sized or screened), with the coarser flake size fractions (below 8 mesh, 8–20 mesh, 20–50 mesh) carefully preserved, and then the carbon contents are determined.