Natural obsidian test stones give precise readings when testing for gold purity. Obsidian is a volcanic glass produced when lava becomes cold. It is been used for years to make the sharpest knives. Obsidian test stones, on the contrary to rougher test stones, have a perfectly smooth surface that provides more consistent and reliable readings.
Natural Obsidian Test Stone
Item #: 7492
Size: 2×3 Color: Black
Case Qty: 1
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