History
Three major companies produced depression glass between the late 1920s to the 1940s: MacBeth-Evans, Federal Glass and Hocking Glass (although there were others). The glassware was cheaply produced with air bubbles, mold marks and other flaws retained within the glass.
Colors
Cobalt blue, pink and green are the most popularly collected colors of depression glass. However, it was also produced in amber, green, pale blue, amethyst, red and many other colors. Glass companies also created a clear version called Monax.
Patterns
The depression glass was not only made in an array of colors, but also in distinguishable patterns. Some of the most popular patterns collected today are Royal Lace, Princess, American Sweetheart, Cameo and Mayfair.
Collecting
Collecting depression glass is a good investment. The pieces will only become worth more as the availability lessens. Learn the basics before starting on this endeavor. Make sure you know which patterns have been reproduced and what to look for in originality.
Value
A mint condition piece of depression glass added to a collection is quite valuable. The glassware should be inspected thoroughly for chips, scratches or cracks. A perfect piece is no longer easy to find.