Abstract: The main object or purpose of the present invention is to provide a glass material that is suitable for mold forming, can reduce the size, and allows rays having a wavelength region between visible light to far-infrared light to pass through. To overcome this object, the present invention provides a glass material allowing rays having a wavelength in the region from visible light to far-infrared light to pass through, the glass material comprising, in terms of molar concentration: 50 to 70% of S, 15 to 30% of Ge, 5 to 20% of Ga, 0.5 to 15% of Ba, and 3 to 15% of at least one member selected from the group consisting of Cl, Br, and I, with the proviso that when the Cl is present alone, the molar concentration is 6 to 15%.

Abstract: A chemically durable porous glass of which the skeleton mainly comprises SiO.sub.2 -ZrO.sub.2 system glass having a ZrO.sub.2 content of 2 or more wt %, and a process for the production of such glass.