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 made as both functional and ornamental objects. This is an inexpensive pressed glass and found in a wide spectrum of colors. Sometimes glass workers refer this as dope glass because the process of applying the iridescent coloring to the surface is called doping. This was made in over 150 patterns and many different pieces from the year 1907 but since it did not command the prices expected it 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.

Millersburg glass Company, Ohio was one of the largest producers of this kind of glass. Though the first glass product of the company were crystal, the Millersburg plant decided to produce iridescent glassware looking to the popularity of it. In this way the Millersburg Company brought out its line of Radium glassware.

Carnival glass has become a popular item for collectors. Some pieces are worth pennies, but hard-to-find pieces can bring in hundreds or even thousands of dollars, making for a wide range in prices. The market is jumping for this antique glass collectible.

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. The prices of this glass vary widely depending on their quality and availability. This glass is a highly collectible item with some of the pieces worth very little, while other, rarer items command thousands of dollars. There is a very active market for this item since it has become an antique glass collectible. Among the greatest producers of this type of glass was millersburg glass in Ohio. It is very hard to identify these products, because the makers didn't consistently mark their work.