Mystery Glass Maker

 Opalescent vase, 17" x 10"

     I found this vase at a local, upscale thrift shop for about $5. It measures approximately 17 inches tall, the base is 6 1/2" in diameter, the mouth is 7" in diameter and it is about 10" at the widest point. There is a sticker on the bottom that reads: "American Hand Blown Glass - Hand blown glassware may show blisters, seeds or thin lines which further enhances it's handcrafted uniqueness". The glass is fairly thin and the finish is applied only to the exterior of the vase. The interior of the vase is pure white. There are many examples found,  using a Google search, of blown glass vases and lamps bearing this label dating from the early and mid 1970s. Many of these lamps can be identified as the work of EF & EF industries, a decorative lamp company located in Chicago during the 70's. I don't know if this company made the glass used in their lamps and if they also made vases, or if they contracted that work, perhaps to one of the many West Virginia glass companies active at that time. This is a fairly fragile piece of glass, and it is somewhat surprising that it has survived, perhaps as many as forty years, in perfect condition. Any help in identifying this glass maker would be most appreciated.