Using the sol-gel route Nd3+-doped oxyfluoride glass-ceramics were prepared. LiYF4 and YF3 crystals were deposited in the glass-ceramics and their size, distribution, and amount ratio were varied by changing the compositions and heating temperatures. The incorporation of Nd3+ ions into both the fluoride crystals was confirmed by the high-resolution elemental mapping of the glass-ceramics. The incorporated Nd3+ ions showed up and down conversion photoluminescence whose properties were obviously different among the samples. The preliminary site analysis for Nd3+ ions was carried out using a unique approach associated with the Prony series approximation. Finally, the approach was found to be useful for the analysis of materials that are structurally complicating.