There are three keys to help with dating most bottles: Side seams: None: bottle may be free blown, in which case it has a very uneven shape and dates before 1860. Or the bottle may have a nice even shape, but was spun in the mold to smooth out the seams; a practice common around 1900-1920.

What is the most expensive piece of Depression glass?

Made by the Jeannette Glass Company from 1929 through 1933, this Cube pink Depression glass butter dish was inspired by the Cubist art movement. The dome is the most valuable part of the dish. The plate alone is often valued at around $9 while the two pieces together sell for around $40.