 The recent claim of superconductivity above room temperature in Pb10-x cucks, Po4, 60 with 0.9x less than 1, referred to as Lk99, has sparked considerable interest, but we have synthesized phase pure single crystals with a copper doping level of x-tilde operator 1 and found that the crystals are highly insulating and optically transparent. X-ray analysis reveals an uneven distribution of the substituted Cu throughout the sample, and temperature, T, dependent magnetic susceptibility measurements for 2 less than or equal to T less than or equal to 800 K reveal a small ferromagnetic component, possibly originating from frustrated exchange interactions in Cu rich clusters in the Pb10-x cucks, Po4, 60 structure. No anomalies indicative of phase transitions are observed, and we rule out the presence of superconductivity in Pb9 Cu, Po4, 60 crystals. This article was authored by P Pup Hal, MyP Aukbar, M Hecting, and others. We are article.tv, links in the description below.