Purity
All gold is an alloy, since it is impossible to remove all the impurities. However, 24K gold is considered "pure gold," even though it is 99.9 percent pure. Fourteen-karat gold is 58.3 percent gold. Gold is usually mixed with silver or copper.
Color
Since 24K contains more gold, it has more gold color and luster than 14K gold. Twenty-four karat gold is a deeper yellow color when compared to 14K gold.
Feel
Fourteen-karat gold is hard to the touch, as are most other metals. Twenty-four karat gold is soft and is easily bent and dented with bare hands.
Uses
Fourteen-karat gold is commonly used in jewelry and other fine luxury items. Twenty-four karat gold is almost exclusively used for gold bullion.
Value
Twenty-four karat gold sells at a very high premium compared to 14K gold. Nearly twice as much gold is contained in 24K gold, and it costs more to purify.