Stained glass is a centuries old art form that dates back to the 7th century, and by the 12th century it was a recognized art form. Not much has changed within the art of stained glass since the 12th century. Stained glass artworks consist of pieces of colored glass held together by a lattice work of lead. Sometimes faces, and other rich details are painted by hand onto the glass. This is most often seen in religious building windows.
There are many different types of glass now available to be used within the stained glass art form. A variety of minerals are added to the clear glass to attain different colors, such as iron oxide, manganese, nickel and selenium. There are several different textured glasses; granite, waterglass and hammered, etc. The lead that holds the pieces in place is in two forms, lead came , which are strips of lead with channels that the glass is placed into and the channels are soldered at the intersections. There is also the copper foil method, in which thin strips of copper foil are placed on the edges of the glass and held in place by an adhesive backing. the pieces of glass are then soldered with lead along all the edges creating a bond along all the seams of the glass.
If you're interested in the process of of how they make the sheets of stained glass, here is a link to a video of the Kokomo Glass Company and how they produce the beautiful sheets of glass. https://vimeo.com/47331192