Nitric acid can turn fake gold green. Genuine gold is highly resistant to nitric acid, while many common metals used in fake gold react with it, causing a green or milky white discoloration.
Here's a breakdown:
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Real Gold: Real gold is a noble metal, meaning it's chemically inert and doesn't readily react with most acids, including nitric acid. Therefore, nitric acid won't turn real gold green.
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Fake Gold (Base Metals): Many fake gold items are made of base metals like copper, brass, or other alloys. These metals do react with nitric acid. This reaction causes the acid to turn green or milky white, indicating the item is not pure gold.
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The Test: The test involves applying a small amount of nitric acid to a discreet area of the gold item. If the acid turns green or milky, it suggests the presence of base metals and the item is likely fake or only gold-plated.
Important Notes:
- Safety: Nitric acid is a corrosive substance. Exercise extreme caution and wear appropriate safety gear (gloves, eye protection) when handling it. Work in a well-ventilated area.
- Concentration: The concentration of the nitric acid can affect the reaction. A stronger concentration will produce a more noticeable reaction.
- Other Acids: While nitric acid is commonly used, other acids like hydrochloric acid (when mixed with nitric acid to create aqua regia) can dissolve gold. Aqua regia is capable of dissolving gold.
- Professional Testing: For definitive identification, it's best to consult a professional jeweler or appraiser. They have access to more sophisticated testing methods.
In summary, while nitric acid does not turn real gold green, it can react with the base metals in fake gold, causing a green discoloration, which can be used to test purity.
