If you've ever wondered whether a gold piece is real gold or some other type of metal, you can find out without taking it to a jeweller or pawn shop. Using equipment and ingredients you already have, you can test the authenticity of gold with a very simple test conducted in your own kitchen.
Rub the gold piece with the clean wash cloth to remove any dust, dirt or contaminants. If there is any stuck-on dirt or grease, get the wash cloth wet and scrub it off.
Use the eye dropper to place two or three drops of vinegar onto the gold piece. If the piece is very small or doesn't lay flat, put the gold into a small bowl so the vinegar can stay in contact with it.
Observe any changes to the gold piece. Gold is a stable metal and does not react with oxygen corroding. Because it is stable, it will not change colours when exposed to vinegar. If the gold piece changes colours, it is not real gold. Gold plate will turn black when exposed to vinegar.
Run the gold piece under cool water or spray it with a water bottle to remove the vinegar.
Rub the gold piece with the clean cloth to dry it.
This test won't hurt your gold. On the contrary, vinegar is commonly used to clean gold jewellery.
Be aware that some gold jewellery may be marked 14k or 18k even though it is not real gold. This is a sly marketing tactic employed by some jewellery dealers.