Vtg Blue Carnival Glasses CSBH (4)

Carnival glass, known for its iridescent shimmer, was produced from the late 19th century through the mid-20th century, often as a less expensive alternative to cut glass. It was typically made by pressing molten glass into molds, which allowed for intricate patterns like grapes, flowers, and geometric designs to be easily replicated. The iridescent effect is achieved by spraying the molten glass with metallic salts before it cools, creating a dazzling, rainbow-like surface. 

The Indiana Glass Company, established in 1904, became a prolific producer of carnival glass, with patterns like 'Harvest Grape' being particularly popular. This pattern, featuring clusters of grapes and leaves, is a classic example of their output and is highly sought after by collectors.