Age changes in the crystallinity of bone mineral and in the disorder of its crystal

The crystallinity of bone mineral and disorder of the crystal at different ages were measured by the X-ray diffraction method of Ruland. Measurements were made on femoral mid-diaphyses of Wistar rat from 2 weeks to 1 year of age. For a given animal age, the crystallinity of bone mineral increases with age, while the overall disorder of the crystal does not vary within experimental accuracy. The increase in the crystallinity with age is attributed to an increase in crystallite size, a decrease in lattice imperfections, or a combination of both effects. It is suggested that lattice imperfections of the first kind more largely contributes to the disorder of bone mineral crystals than those of the second kind.