In the paper, the detail features of karite – the diamond (diamond-containing) fossils of the Kara meteorite crater formed after organic matter, generally after wood fragments, studied by a wide list of modern analytical methods are presented, including structural data at atomic resolution level, chemical composition and spectroscopic characteristics. The diagnostic features, formation mechanism and ontogenic specificity are analyzed. As a result of a detailed study of the ontogenetic specificity, structural and chemical composition of the diamond fossils a fundamental difference in the mechanism of formation from typical paramorphoses and pseudomorphoses has been established, there they have been classified as pseudo-paramorphoses. Taking into account special conditions for the described aggregates of diamond and other forms of carbon formation from organic matter by impact, it is proposed to differ a special variety of fossils – impact fossils. The prospects for using of the diamond fossils for geological studies and application in carbon materials field are estimated.