买金、卖金必看！黄金、24K金、18K金有啥区别？回收黄金如何检测？

Group 1: Overview of Precious Metals - The recent surge in gold prices has made precious metals like gold, platinum, and 18K gold popular topics of discussion [1] - Gold is pure gold, platinum is an independent silvery-white metal, and 18K gold is an alloy containing 75% gold mixed with other metals [2] Group 2: Gold Specifications - According to national standards, gold purity is defined as Au999 (not less than 999‰) for the highest purity jewelry, while Au990 (not less than 990‰) is known as standard gold [3] - 24K gold theoretically has a gold content of 100%, representing the highest purity, but is rarely used in traditional jewelry due to its softness [4] Group 3: Platinum Characteristics - Platinum, with the chemical symbol Pt, is often mistakenly referred to as "white gold" but has no chemical relation to gold [5] - Common purities for platinum include Pt990 (not less than 99% platinum) and Pt950 (not less than 95% platinum) [5] Group 4: 18K Gold Composition - 18K gold contains 75% gold and 25% other metals such as silver, copper, or palladium [6] - Different colors of 18K gold are produced based on the added metals, with 18K white gold containing palladium or nickel, and 18K rose gold having a higher copper content [7][9] Group 5: Gold Recovery and Testing Methods - Various methods exist for testing the authenticity and purity of gold, including: - Fire assay, which is highly accurate but destructive and time-consuming [10] - X-ray fluorescence, a non-destructive method that provides quick results but may be affected by surface coatings [11] - Density method, which is simple and cost-effective but less accurate for complex shapes [12] - Acid test, which is low-cost but carries corrosion risks and is subjective [13] Group 6: Recommendations for Gold Recovery - It is crucial to choose certified institutions (CMA/CNAS) for gold recovery to ensure accurate testing results [14] - Caution is advised against recovery points offering prices significantly above market rates, as they may be traps [15]