What is the most expensive piece of Fenton glass? The most expensive piece sold was a piece of Fenton Karnak's red piece of art glass that sold in 2014 for $15,000.00, which was part of the Fenton Art Glass Museum. Many USA companies, including Hobbs Brockunier & Co, Fenton Art Glass, Westmoreland Glass, Kemple Glass, and several British companies, have made Hobnail Glass. Today it is also imported from China and Taiwan. The Fenton cranberry glass colour comes from pure gold. Glass colours (yellow or green) containing uranium will fluoresce under black light. Fenton ceased "traditional" glassmaking at the Williamstown, WV factory in July 2011. However, the factory remained a jewellery-making operation, producing handcrafted glass beads and Teardrop earrings. Fenton started the Fenton Art Glass Company in a rented space in Martins Ferry, Ohio. The Fenton factory is built in Williamstown, West Virginia. The first piece, made on January 2, 1907, is a crystal cream pitcher with a Water Lily and Cattails pattern. Pre-1958 Fenton milk glass is said to be easily distinguishable because it is less dense and less opaque than their milk glass made from 1958 onwards. Most green-coloured Depression Glass pieces have trace amounts of uranium, making the glass glow under black lights. (The radiation levels are insignificant and less than our daily exposure from other sources.) Look for a Fenton tag (used before 1970), look for the Fenton mark ("Fenton" in an oval), and look for "F" in an oval, indicating another company's mould was used (1983+). (See below for more info on marks.) If you are looking for high quality, high purity and cost-effective zinc sulfide, or if you require the latest price of zinc sulfide, please feel free to email contact mis-asia.