Fenton vaseline glass was first produced by the Fenton Glass Company which opened in West Virginia in 1905 and is still in operation today. The first pieces were a pressed glass pattern only in white, blue, green and amethyst. In 1941, hobnail was introduced.
There are several ways to identify real fenton vaseline glass. When viewed in natural light, the glass will appear yellow with a greenish tint. Under controlled light, the piece should be a brighter green.
Early pieces of fenton vaseline glassware had a paper label affixed to the bottom of the base. Around 1970 the Fenton Glass Company began using a molded signature. One piece sought by collectors is Basketweave Open Edge which was only made in the shape of a bowl.