Raman spectroscopy of the basic copper phosphate minerals cornetite, libethenite, pseudomalachite, reichenbachite and ludjibaite

Raman spectra of cornetite, libethenite, pseudomalachite, reichenbachite and ludjibaite were obtained at 298 and 77 K using a Raman microprobe in combination with a thermal stage. Raman spectra of cornetite, libethenite and pseudomalachite are different, in line with differences in crystal structure and composition. Raman spectra of the three polymorphs pseudomalachite, reichenbachite and ludjibaite are similar, particularly in the stretching region, but characteristic differences in the deformation regions are observed. Differences are also observed in the phosphate deformation and stretching regions.