This stone is ideal for use with test acids and testing solutions to determine karat of gold. It is made of natural stone, is easy to work with and convenient for your workspace, or those on-the-go. This stone measures 6" x 4" x 3/8"

Find this tool at: http://www.jewelrytools.com/eurotool/jewelry-testing-supplies/Natural-Test-Stone-6-by-4-by-3-8-Inch.html

Find more at http://www.jewelrytools.com