Various compositions of P2O5-TeO2-ZnO glasses were prepared by using a combinatorial glass preparation system including a batch-preparing apparatus and a multi-sample casting machine, and the compositional dependence of glass forming tendency and thermal properties were intensively investigated. The samples exhibited a variety of colors, such as transparent, yellow, wine red and brown depending on its composition. Analyses with scanning electron microscopy and X-ray photoelectron spectroscopy revealed that the reddish coloration is responsible for colloidal suspension of nanometer sized elemental Te particles.