Raman microprobe studies of individual microcrystals of diamond and of thin diamond films deposited by the hot-filament chemical vapor deposition (CVD) method are focused on the determination of the purity of the diamond phase and on the extent and nature of defects of the diamond structure. The findings are discussed in relation to deposition parameters, growth mechanisms, and diamond morphology. The specimens consisted of single microparticles of sizes 3 to 40 µm, particle clusters, and continuous polycrystalline films of 3 to 8 μm thickness grown on silicon substrates. The interpretation of the results is based on the line shape, line width, and frequency position of the diamond line nominally at 1333 cm-1 Raman shift, as well as on other characteristic Raman bands in the region 1300 to 1600 cm-1 attributed to graphitic carbon components. Examined also are the relationship of the spectral background signal to the signal of the Raman features. Luminescence emissions arising from either structural imperfections or substitutional impurities in the diamond lattice are observed. A luminescence band centered around 738 nm (1.68 eV), attributed to either the neutral lattice vacancy in diamond, or possibly a silicon pair substitution in the diamond lattice, widely varied in intensity among the samples analyzed. The observation of this photoluminescence band is correlated with results from concurrent cathodoluminescence measurements.