The ornament, if made of pure gold, would be 24 carat gold, as 24 carat represents 100% gold and is the highest purity level for gold.
If a gold ornament is made of 12 carat gold, meaning the ratio of gold to copper is 1:1, then it implies that the ornament consists of 50% gold and 50% copper, since 12 carat gold is 12 parts gold out of 24 possible parts.
Pure gold is 24 carat gold, which means it is made of 100% gold with no other metals mixed in. Therefore, if the ornament originally made of 12 carat gold were made of pure gold instead, it would be considered 24 carat gold. This is because 24 carat is the measurement used to denote pure gold.
The term carat here refers to the purity of the gold, and pure gold is classified as 24 carat because it is the most refined form available. The higher the carat number, the greater the purity of the gold. Therefore, in terms of carat measurement, pure gold will always be 24 carat.