Acid Testing Stone 2 1/2 X 1 1/2 X 0.5 " (6 piece min)

Acid testing stones are for testing the karat content of gold, and the purity of silver and platinum. When using testing acid, use this stone for scratch testing. Jet black material. 2.5 X 1.50 X 0.50” (6.3 x 3.5 x 1 cm)