- 4 Pcs set that consists: 18K, 20K, 22K, 999S
- Mainly used for testing the fineness of gold and silver.
For testing the gold fineness:
1. Scratch the item on the gold test stone, and scratch the gold test needle next to it.
2. Pour a drop of testing acid across both marks, and observe how it reacts to the acid.
3. If the scratch marks of item react the same as the gold needle scratch, means that the fineness is same as gold needle. If scratch marks of item dissolves faster than the gold needle scratch, the fineness is lower than the test needle. If scratch marks of item dissolves slower than the gold needle scratch, the fineness is higher than the test needle.
For testing the silver fineness:
1. Scratch the item on the test stone, and scratch the silver test needle next to it.
2. Pour a drop of testing solution across both marks, and observe how it reacts.
3. If the scratch marks of item dissolves faster than the silver needle scratch, the fineness is lower than the test needle. If scratch marks of item dissolves slower than the silver needle scratch, the fineness is higher than the test needle.
4. Colour changes of testing solution
Dark Red: 90-99%
Light Red / Brown: 80-90%
Light Green: 65 - 75% or lower
Note: These method of gold testing & silver testing are entirely subjective, requires experienced observation and practice from respective master's guidance.