R1353B Art Nouveau-Style Mt St Helens Swiss Blue Helenite Prong Set Sterling Silver Ring Gemstone: Helenite - Fused Volcanic Ash From Mt. Saint Helen's, WA Stone Cut: Pear Stone Size: 4.5ct - Approximately 13mm x 18mm (0.47" x 0.67") Metal: 925 Sterling Silver Color: Swiss Blue Setting: Prong Origin: Washington, USA *The cutting of the stone might be different from what is shown on the photos, depends on the availability in stock. *Because we use natural stones, the stones may vary slightly in shape, size, and color. About Helenite: Helenite is a gemstone that resulted from volcanic ash and rocks, and is also referred to as emerald obsidianite, Mount St. Helen obsidian. The volcano erupted on May 18, 1980, and ejected igneous rock from 10-20 miles underground.