Precious Metals Testing Kit Silver, Platinum, 10k 14k 18k ...
Precious Metals Testing Kit Silver, Platinum, 10k 14k 18k 22k Gold INSTRUCTIONS TESTING GOLD OR PLATINUM Using PreMixed Acids with a Test Stone. Rub the jewelry on the test stone using four firm strokes (two forward and two back) so that a noticeable streak of metal is on the stone. Apply a drop of the premixed acid to the center of the streak.