Instructions
Look at the color. The majority of Fostoria crystal is clear, especially if it is from the American pattern. However, blue and red colored crystal were used in the Argus pattern. Green crystal, sometimes called "Depression green" wasn't used in any Fostoria patterns.
Perform a black light test. Fostoria crystal will have a light yellow tinted hue when lit with a black light in a dark room.
Check the clarity of the glass. It should be smooth and clear. Fostoria fire polished all of the pieces it made, which prevents cloudiness.
Inspect the seams. Because of the intricacy of the Fostoria designs, you should find at least three seams. Most of the knock-offs only have two seams.
Know the specific characteristics of different types of Fostoria pieces. For example, a Fostoria pitcher handle will always be attached at the very top of the pitcher. Other manufacturers will attach the handle at least 1 inch from the top. Footed pieces have straight sides and an S-shaped front foot profile. Straight pieces, such as vases, will have a curved profile with a flared top.