Structural work has determined that its 1,494 Dalton core unit (Glycine / Hydroxy-glycine / FeO) contains iron, but not lithium, leading to the more general term hemoglycin for these molecules. The hemoglycin core contains a total of 22 glycine residues in an anti-parallel beta sheet chain that is terminated at each end by an iron atom plus two oxygens. Four of these glycine residues are oxidized to hydroxy-glycine with hydroxy groups (-OH) on the alpha carbon. This structure was determined by mass spectrometry of meteoritic solvent extracts and has been confirmed in X-ray scattering by crystals of hemoglycin, and also by optical absorption. Crystals show a 480 nm characteristic absorption that can only exist when hydroxy-glycine residues have R chirality and are C-terminal bonded to iron.