The identity of diamond inclusions in quartz-muscovite gneisses occurring in the Saxonian Erzgebirge near the Saidenbach reservoir was proven by laser-Raman micro-spectroscopy. The identification was additionally backed-up by graphitization of diamond inclusions as a result of irradiation with a high-energy laser beam. Enclosed microdiamonds are mostly idiomorphic and are up to 30 μm in size. They occur preferentially in garnet but were also found in zircon and kyanite. The microdiamond inclusions give evidence for ultra-high pressure metamorphism experienced by the host rock.