Late 1800’s Black & White Slag Glass Candy Dish with tones of purple and blue

The first pressed glass pieces that collectors refer to as "slag glass" were made in the 1890s, using the glass-like by-product of iron ore known as-you guessed it-slag. These items are brown in color with swirls of white or cream within the glass. Other types of metal ores produce different colors of slag when they are refined.