Stone for testing gold with test acid.

Testing with stone:

1. Use the item for testing to make a mark of 3-4 cm on the stone.
2. Apply a drop of the 8 ct. test acid.
3. If the mark is unchanged, the fine gold content must be higher. Apply a drop of the 14 ct. test acid etc.
4. When the mark rises, the fine gold content matches the fine gold content noted on the test acid.
5. Clean the stone after use with kontrastol.

Size: 60 x 40 mm