Carnival Glass was initially called Iridescent Ware when it was introduced in late 1907. The name carnival glass was not commonly used until collectors in the 1950s began to refer to it as such. This innovative glassware typically featured a vivid metallic sheen of changing hues on pressed glass articles made in highly-patterned moulds. The secret behind the Iridescent Ware was a special spray of metallic salts on the glass while it was very hot.

Carnival glass is a colored, inexpensive pressed glass that was used to make both functional and ornamental objects. It can be found in a wide range of iridescent colors. Carnival glass is sometimes called dope glass by glass workers because doping is the process of applying the color to the glass surface. Carnival glass production started in 1907. It was used in production of many different pieces and in more than 150 patterns. However, since it did not command the prices expected, it was subsequently discounted.

This glass is made in many translucent colors like primarily amethyst, marigold, cobalt, green, and red. It is also made in opaque white, which is referred to as milk glass. Before the hazards of radiation were well known, the glass was also made in semi-transparent or translucent pale green and was named as Vaseline or uranium glass. Vaseline glass and uranium glass contain traces of uranium salts in the glass which can make a faint green glass glow in reaction to UV light.

Among the greatest producers of this type of glass was Millersburg glass Company in Ohio. The first glass products by that company were crystal however the Millersburg plant decided to follow success for iridescent glassware. So in the beginning of 1910 the Millersburg Company started its line of Radium glasswares

Carnival glass is a collector's item. Prices of these glasses vary wildly from a few dollars to thousands of dollars. Carnival glass has become antique glass collectible and there is a good active market for it.

The identification of the glass of carnival is as an operation much difficult one. Great part of the suppliers has not included the mark of the creator in their product, while the others have made therefore only for the part of the time that have produced the glass. In order to identify this glass, one must bind together the models, colors, splendor, edges, thickness and other factors from catalogue of the old supplier, other known examples, or the other material of reference. From many suppliers the produced near copies of the popular models of theirs available again, identifying it are a challenge also for an expert.

At the time of introduction in late 1907 the carnival glass was called as Iridescent Ware. However, people started using the name carnival only after collectors in the 1950s began to refer to it as such. Among the greatest producers of this type of glass was Millersburg glass Company in Ohio. The first glass products by that company were crystal however the Millersburg plant decided to follow success for iridescent glassware. There is a very active market for this item since it has become an antique glass collectible. So even for an experienced expert this is a hard task.