In the mid to late 1800's, table lamps began replacing the candlestick and lantern for interior lighting. With the advent of better technologies in wicks and mantles, lamp became brighter and it became popular to place a shade over the burner. While the shade helped reduce the glare of the burner, it also created a nice ambiance to the lamp.
Table lamps with glass shades are generally referred to as student lamps and their shades are referred to as student lamp shades. Student shades are known for their overall general shape; wide fitter on the bottom, bulbous body, neck and top. Although student lamp shades were made in a vast variety of sizes, shapes and colors, the shades can be placed in about seven general categories: cased, hobnail, melon, opal, quilted, ribbed, and Tam-O-Shanter.
When looking at student shades, notice the slight variations among the styles. For example, a ribbed shade can be a plain rib or a rib swirl and can have a plain top or a crimp top. Ribbed shades also come in a range of sizes from 4" to 10".