To determine if a yellow piece of metal found in a stream is real gold, several tests can be performed:
- Visual inspection: Real gold has a distinctive brassy yellow color and is malleable (can be dented). It often does not have sharp edges if it has traveled far in the stream.
- Magnet Test: Gold is not magnetic, so use a magnet to check if the metal piece is attracted to it. If it is, it's not gold.
- Density Test: Gold has a high density (~19.3 g/cm³). Weigh the piece and measure its volume by water displacement to calculate its density. Real gold will be much heavier than equivalent volume of most other metals.
- Streak Test: Scratch the metal on unglazed ceramic or tile. Real gold leaves a yellowish streak, while fool's gold (iron pyrite) leaves a greenish-black streak.
- Acid Test: Can be done by making a small scratch on the metal and applying nitric acid. Real gold will not react, while other metals will.
- Hardness Test: Gold is soft and malleable; it will dent or deform if bitten or scratched, unlike many other metals.
These simple field tests help differentiate real gold from fool’s gold and other yellow metals often found in streams.