The Vitro Agate Company was founded in 1932 in Parkersburg, West Virginia by a number of glassworkers with experience in marble-making, the ownership and location of their marble works changed often throughout the life of their company, in at least three different states, their name not being trademarked or protected, numerous entities used the same name by simply adopting the name to use as their own. Early Vitro Agate marbles are the brushed variety. This is the type that has a thin layer of colored glass brushed on a base color. There are also a few veneered varieties, but these were manufactured later on.