If you enjoy unique, collectible glassware then you will be interested in a small art glass company named Fenton Glassware. It was founded in 1905 by the Fenton brothers in Ohio. The brothers had a huge interest in colored glass. They became the ones responsible for producing the highly famous carnival glass. Over the years special colors of their highly popular carnival glass have been introduced along with revived special colors. They also have limited edition colors that have been released along with limited edition glassware lines.
Fenton glassware produced not only carnival glass but also opalescent glass which has a milky and pearly appearance, overlay glass which has a glass interior and color covering, transparent and opaque glass.
You can identify their glass made before 1952 by a mold number. Identifying after 1952 they began using ware numbers which consisted of 4 digit number followed by a 2 letter code. These are used to not only date the piece by also value the glass item. They also have added various logos to their items through the years which helps in dating and valuing the items as well. You can find mold numbers, logos, and ware numbers in collectors references.