Photoluminescent porous silicon has been produced in a variety of etchants using laser-assisted etching of silicon without an applied potential. Porous silicon (por-Si) produced from etchants containing K+, Cs+, or Rb+ can have cubic crystallites of hexafluorosilicate on top of and embedded in the porous silicon film. These are formed during etching from the metal ion and the etch product, SiF62-, via heterogeneous nucleation and growth. The photoluminescence of the hexafluorosilicate-coated por-Si on excitation with UV light is blue-shifted (590-610 nm), as compared to porous silicon that shows red photoluminescence (similar to640 nm), even though the pure hexafluorosilicates exhibit no photoluminescence of their own.