At the time of introduction in late 1907 the carnival glass was called as Iridescent Ware. However, people started using the name carnival glass only after collectors in the 1950s began to refer to it as such. This innovative glassware made in highly patterned moulds had a vivid metallic sheen of changing hues on pressed glass articles. Iridescent Ware got the metallic sheen from 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.

The glass is produced in various translucent colors. Primarily amongst these are amethyst, marigold, cobalt, green, and red. Sometimes it is also made in opaque white which is called milk glass. A semi-transparent or translucent pale-green hue was also available before the widespread knowledge of radiation hazards. this glass was called Vaseline or uranium glass. Both of these contain traces of uranium salts which gives the glass a faint green glow when exposed 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

The prices of Carnival 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.

Identification of carnival glass is very difficult task. Most of the manufacturers did not include a maker's mark in their product, while the others did so only for part of the time they produced the glass. To identify this glass, one has to match patterns, colors, sheen, edges, thickness, and other factors from old manufacturer's trade catalogs, other known examples, or other reference material. Since many manufacturers produced close copies of their rivals' popular patterns, identifying it is a challenge even 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.