A comprehensive set of experiments to simulate lunar surface materials is outlined and the first phase in the experimental procedure is described in some detail. Possible lunar-type lavas are generated and physical measurements, made on these lavas and other rocks in natural and powdered form, include those of porosity, spectrophotometry, polarimetry, and thermal conductivity. Comparison of the results with those for the Moon indicate that (a) certain named materials which have not suffered alteration through exposure to the solar wind are possible candidates for a lunar surface model; and (b) lunar lava flows are probably of basic to intermediate, rather than acidic, composition. Magmas of acidic composition may be expected to generate volcanic domes and pyroclastic deposits.