China has developed a groundbreaking form of 24K gold known as Hard Pure Gold (硬足金) — a metallurgical innovation that merges the purity of traditional 24-karat gold with the hardness and durability of lower-karat alloys. This new material, which now dominates China’s jewelry market, is the result of nanocrystalline engineering and microstructural refinement that fundamentally change how gold behaves at the atomic scale.