One of the main indicators of carnival glass is that it is always iridescent, and will have some type of decorative color. The reason these pieces get their sheen is because the glass is tinted with metallic salts while it is still hot from the pressing, and then the glass is re-fired. This is what helps to make it so beautiful. While this type of antique glass is most associated with the United States, it was also produced in Great Britain, Australia, and several other countries.

Some nations, mostly Asian, still make carnival glass even today, in every spectrum of color from yellow and green to blue, red or pink. The irony of this is that this type of glass was initially meant to be a high end expensive glass, but early on it did not catch on the way most glass companies thought it would. After it was consistently marked down, it gained rapid popularity, eventually becoming the glass companies expected, but this design was not consistently referred to as "carnival glass" until the 1950s when collectors began using the term.

Fenton glass was the first and largest producer of carnival glass, producing many different pieces in over 150 patterns. Like other types of glass made by Fenton, they were well known for quality, and they were also one of a very few makers who made a red version of these pieces.

Due to the resurgence in popularity, carnival glass is now being remade by several glass companies after decades without any production at all. Fenton was one of the companies that began re-making modern examples before they decided to close down. While the newer stuff is popular, the antique carnival glass is even more so and is as valuable as it is beautiful.