The Fostoria Glass Co. produced the American pattern from 1915 until 1986. Its raised pyramid design is the most commercially successful pattern ever produced, according to Ann Kerr, author of "Fostoria: Identification and Value Guide of Pressed, Blown, and Hand Molded Pieces." The pattern's popularity inspired many imitations. Glass collector Toby Aulman of AuctionBytes states that the Jeanette Glass Co. ran a similar Cube pattern from 1929 to 1933. Indiana Glass Co. had a comparable Whitehall pattern in the 1950s. Look-a-like patterns can confuse glass collectors, but its possible to identify the Fostoria American glass by color, finish and the number of seams.
Look for colorless glass. Most pieces in the Fostoria American pattern are clear with few exceptions. Pieces in the Cube pattern are frequently pink or green.
Check for a fire-polished surface. Fostoria American glass has a smooth finish because pieces were returned to the furnace to soften the edges. Whitehall Indiana glass has a rough finish because the pieces were not fire-polished.
Count at least three mold marks. The majority of Fostoria American glass has three seams with a few rare exceptions. Whitehall usually has two seams.
Identify Fostoria American glass by the ground bottom. Feel for a flat, level base rather than a pressed bottom.
Fostoria did make a few pieces of American glass in ruby. Look for three seams except on the following: plates, banana splits, 14-inch spun glass punch bowls, the twin salt dip and the glass-handled cake plate, according to the Glass and Pottery Sellers Association.