Carbonate Fluorescence. The spectrum on the left side of the graph is the tail end of the excitation peak. The rising spectrum on the right side of the graph is the beginning of the 2 λ peak. The 2 λ emission peak is an artifact of the grating within the Shimadzu Fluorometer and is not likely due to mineral fluorescence. Furthermore a 1.5 λ emission peak can be seen for the carbonates. This also is likely due to the instrument conditions rather than mineral fluorescence.