Dichroic glass is glass which can display multiple different colors depending on lighting conditions. One dichroic material is a modern composite non-translucent glass that is produced by stacking layers of metaloxides which give the glass shifting colors depending on the angle of view, causing an array of colors to be displayed as an example of thin-film optics. The resulting glass is used for decorative purposes such as stained glass, jewelry and other forms of glass art. Modern dichroic glass is available as a result of materials research carried out by NASA and its contractors, who developed it for use in dichroic filters. However, color changing glass dates back to at least the 4th century AD, though only very few pieces, mostly fragments, survive. It was also made in the Renaissance in Venice and by imitators elsewhere; these pieces are also rare.