Solution: Pure gold is 24-carat.

Karat, also spelt Carat, is a measure of the fineness (i.e., purity) of gold. A gold karat is 1/24 part, or 4.1667 per cent, of the whole, and the purity of a gold alloy is expressed as the number of these parts of gold it contains.

Pure gold ornaments, such as those made of 24-carat gold, are extremely rare since pure gold is highly delicate and prone to wear and tear.