Economy black "glass" stone is used with solutions and test needles to determine the karat value. Measures: 2" x 1-1/2" x 3/16".<br /><br />Find this tool at: http://www.jewelrytools.com/eurotool/jewelry-testing-supplies/Gold-Test-Stone-Economy-Test-Stone.html<br /><br />Find more at http://jewelrytools.com
