American cut glass is a very valuable collectible on the antiques market. Values range based on quality, maker, condition, and pattern and many pieces regularly are worth $1,000 to $100,000.
Another way to sound test the glassware is to lightly run a wet finger in a circular motion around the rim. If it's crystal, you will be able to hear a subtle tone that emanates from it. With a close eye, inspect the sharpness or smoothness of the cut. The smoother it is, the more likely it's crystalware.