pure gold; solid gold
Refers to gold that is unalloyed and of high purity, often used for jewelry, coins, or decorative items.
この指輪は金無垢でできている。
This ring is made of pure gold.
金無
A solid gold watch is very expensive.
Compound of 金 (kin, 'gold') and 無垢 (muku, 'purity, innocence'), literally 'gold purity'.