Graphite is the odd one out because it is the only non-metallic element in pure form among the options. Diamond is a crystalline form of carbon but has a different structure. Mica and asbestos are silicate minerals. However, the key distinction is that graphite is an allotrope of carbon with electrical conductivity, while the others are insulators or have different properties. The most likely classification is that graphite is conductive while the others are not.