Undocumented glassware such as these pieces with no provenance or markings are very difficult to identify and is generally referred to as “Studio Glass” or “Art Glass”, after the fact it is often the product of small private glass studios. Most of it is European, notably Murano Italy and dates from the second to third quarter of the 20th Century. Similar wares are still in production in glass studios on both sides of the Atlantic.
Studio glass is often experimental, the glass itself of varying thicknesses and temper, which means it can crack if exposed to rapid swings in temperature. If washed, room temperature water should be used. Values for undocumented pieces depends a great deal on their decorative value and design, with examples comparable to those documented to be by well known makers being the most sought after. In the Current market comparable examples to the ones pictures above often sell at auction in the $75.00- $150.00 range