In order to inspect a gold piece’s authenticity, whether in the form of jewelry or not, examining, pinpointing and identifying gold hallmarks aren’t enough. Even the customary practice of “bite-it-with-your-teeth” approach simply doesn’t measure up anymore.
These days, there is a wide assortment of alloys available that can be be mixed in with gold elements. That’s why determining the genuineness of a gold piece has become a science, and the most commonly used method, because of its instantaneous result and economical value, is the gold acid test.
The gold acid test proliferated in the second half of the 19th century during the time when the California Gold Rush was the talk of the day. Gold prospectors, as well as gold dealers, had to be able to differentiate gold apart from base metals then.
Theoretically, gold acid test is any form of a chemical qualitative test that makes use of a strong acid like nitric acid, hydrochloric acid and potassium dichromate in order to distinguish gold from base metals. It is because unlike other metals, gold doesn’t react to most acids (except to a mixture of nitric acid and hydrochloric acid called “aqua regia”).
Using the gold acid test in determining a gold piece’s purity or Karat can be done in any of the following ways:
- Acid testing kits,
- Touchstone testing
- and Electronic gold test.
Gold Acid Testing Kit
A Gold Acid testing kit contains a color reference chart and bottles of different acid formulas that react in various ways depending on the gold properties they come into contact with. By placing a drop on the item using the formula corresponding to the lowest karat first, then observing its chemical reaction, and comparing it against the color reference chart, the purity and the karat of the gold are determined.
For touchstone testing, the gold sample and a known-gold item are rubbed against the stone leaving gold samples behind. Using drops of acids designed for different karats, the purity and the karat are identified.
Electronic Gold Test
Employing the use of an electronic box, gold is tested by putting a test solution or acid unto the test plate then submerging the gold item into the testing solution. The result is then analyzed by the gold reference test plate.
Given those gold acid test practices, deciding which method to perform is simply a matter of choice. Also, always exercise caution when dealing with acids as they are extremely corrosive and toxic.
By Mike Ferreira on November 9th, 2011