Bachman, C. H., & Ellis, E. H. (1965). Fluorescence of bone. Nature, 206(4991), 1328–1331. doi.org

The 1965 study by Bachman and Ellis investigated the visible fluorescence of clinically normal human and dog bone under ultraviolet radiation excitation at 3650 Å. The results revealed that all whole bone samples exhibited a consistent spectral pattern characterized by a major emission peak at approximately 4400 Å (blue light) along with two minor, erratic peaks at 5900 Å and 6400 Å. By comparing whole bone to isolated bone components, geological apatites, and pure calcium compounds, the researchers found that while all calcium-bearing samples shared the 4400 Å peak, whole bone and collagen displayed significantly higher fluorescent efficiencies than decollagenated apatite or pure chemical compounds. The authors concluded that the structural combination of collagen with internally bound apatite crystals serves as the primary source of bone fluorescence, with collagen acting to heavily enhance the weaker intrinsic properties of the apatite crystals, potentially utilizing trace copper as a sensitizer for the blue emission band and iron as an activator for the higher wavelength peaks.

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