Necessary, but not sufficient: Raman identification of disordered carbon as a signature of ancient life.

To identify microscopic particles as actual fossil material, it would be useful to have a means of unambiguously recognizing which carbonaceous deposits found in rocks are residues from once-living organisms (i.e., biogenic material).

Lack of OH in nanocrystalline apatite as a function of degree of atomic order: implications for bone and biomaterials.

Using laser Raman microprobe spectroscopy, we have characterized the degree of hydroxylation and the state of atomic order of several natural and synthetic calcium phosphate phases, including apatite of biological (human bone, heated human bone, mouse bone, human and boar dentin, and human and boar enamel), geological, and synthetic origin. Common belief holds that all the studied phases are hydroxylapatite, i.e.