Carnival Glass, originally called Iridescent Ware, first came out in late 1907. It was not commonly referred to as Carnival Glass until the 1950s, though, when collectors started calling it that. These pieces were typically made from extremely ornate glass pieces, characterized by the myriad hues of their sheens. Their luster was achieved by applying metallic salt sprays to the glass before it had completely cooled down.

Carnival glass is an inexpensive pressed glass, made as both functional and ornamental objects, found in a wide spectrum of colors. This glass is sometimes referred to as dope glass by the glass workers because the process of applying the iridescent coloring to the surface is called doping. Its production started in 1907 in many different pieces in over 150 patterns. However, it did not command the prices expected, and was subsequently discounted.

This glass is available in many translucent colors like primarily amethyst, marigold, coblat, green and red. It is also made in opaque white which is also referred to as milk glass. This glass was also availale in semi-transparent or translucent pale green and was named as Vaseline or uranium glass before the harmful effects of radiation were known. Vaseline glass and uranium glass have small amount of uranium salts which make faint green glass glow on reaction with UV light.

One of the largest producers of this kind of glass was Millersburg glass Company, Ohio. The first glass products of the company were crystal, but the Millersburg plant decided to ride the wave of enthusiasm for iridescent glassware. Thus, in early 1910, the Millersburg Company brought out its line of Radium glassware

Carnival glass is highly collectable item. Prices vary widely, with some of the pieces worth very little, while other, rarer items command thousands of dollars. It has become an antique glass collectible and there is a very active market for it.

It is very hard to identify carnival glass. Most of the time, the makers didn't mark their work, others only marked them part of the time. To figure out who made the glass one has to match, patterns, colors, sheen, edges, thickness and some other factures from old trade catalogs, examples of prior work or a reference material. Many manufacturers made dlose copies of rivals popular works to. So even for an experienced expert this is a hard task.