Real gold does not burn like wood or paper. Gold is a unique and stable element, and its properties explain its behavior when exposed to heat.
Why Real Gold Doesn’t Burn
Gold’s resistance to burning stems from its intrinsic chemical properties. It is classified as a “noble metal,” known for exceptional unreactivity. This means gold does not readily combine with oxygen or other elements, even when subjected to high temperatures. Burning, or combustion, typically involves a rapid reaction with oxygen, releasing heat and light; gold does not undergo this type of chemical reaction.
Unlike metals such as iron, which can rust, or wood that combusts, gold remains largely unaffected by exposure to air and moisture. Its inertness allows it to resist corrosion and tarnishing, maintaining its appearance. This chemical stability makes gold a durable material, valued for centuries in jewelry and coinage.
What Happens When Gold Gets Hot
While gold does not burn, it reacts to heat by undergoing a physical change: it melts. Pure gold has a relatively high melting point of approximately 1,064 degrees Celsius (1,947 degrees Fahrenheit). When heated to this temperature, solid gold transforms into a liquid state without chemical alteration. Upon cooling, it solidifies back into gold.
Many gold items, particularly jewelry, are alloys—gold mixed with other metals to increase hardness and durability. These alloys often have different, usually lower, melting points than pure gold. For example, 18-karat gold melts around 926 degrees Celsius, while 14-karat gold melts around 879 degrees Celsius, depending on the specific metals used. Household fires typically do not reach temperatures high enough to melt pure gold, though extreme heat from industrial processes or specialized torches can achieve this.
Using Fire to Test Gold: The Truth
Using fire, like a lighter or small torch, to “test” if gold is real is a common notion. Proponents suggest that real gold will not tarnish or change color, while fake gold might blacken, smoke, or even melt. While genuine gold does not turn black or darken when heated, unlike some base metals that oxidize, this method is not a definitive or safe test for authenticity or purity.
Attempting to test gold with fire at home can be risky, potentially damaging the item or causing injury. The heat from a lighter is often insufficient to differentiate pure gold from certain alloys or plated metals, and it cannot accurately determine the gold’s karat. More reliable methods for testing gold include acid tests, which observe reactions to specific acids, or specific gravity tests, which measure density. Professional jewelers and appraisers use advanced techniques like X-ray fluorescence (XRF) analyzers to determine gold’s composition and purity without damage.