Considering the high economic importance and worldwide distribution of gold, the ability to identify its provenance is critical and challenging to ensuring a responsible supply chain from deposit to consumer, especially within conflict-affected areas. Here we present an innovative approach to trace the provenance of natural gold from French Guiana through a combination of geochemical and statistical methods. This approach is divided in three steps and allows the identification of illicit gold, the certification of the declared gold origin coming from legal operators and, in some cases, the identification of unknown gold. French Guiana was chosen as a demonstration case of our approach because it is a well-known conflict-affected area where illegal mining is widespread. In the first step, we showed that the use of illegal Hg amalgamation can be easily revealed by looking the gold grain morphology with an optical microscope or by detecting the Hg with laser-induced breakdown spectroscopy that allow direct detection on the field. In the second and principal step, we demonstrated that a declared provenance of gold can be certify with a high degree of confidence by measuring the Ag content of a gold grain population and by checking it against a database with the Kolmogorov-Smirnov statistic. In the final step that allows the identification of the origin of unknown gold, we used (i) the content of minor elements (Cu and Hg), (ii) the identification of mineral inclusions and their relative proportions within samples and (iii) the trace element composition of natural gold grains determined by LA-ICP-MS and coupled with a permutational multivariate analysis of variance and a similarity percentage analysis. This method allows the identification of the provenance of 69% of the gold samples; the provenance of other gold populations (31%) cannot be identified because of their geological similarity with other groups. The traceability of natural gold can be guaranteeing with our innovative approach, in particular by certifying declared gold population provenance. Further challenges to be addressed will be the implementation of such approach in others conflict-affected regions to support the global supply chain of gold.

考虑到黄金的高度经济重要性和全球分布，确定黄金出处的能力对于确保从存款到消费者的负责任的供应链（尤其是在受冲突影响的地区）至关重要且具有挑战性。在这里，我们提出了一种创新方法，通过地球化学和统计方法的结合来追溯法属圭亚那的天然金的来源。这种方法分为三个步骤，可以识别非法金，对合法经营者申报的黄金来源进行认证，在某些情况下还可以识别未知金。选择法属圭亚那作为我们方法的示范案例，因为它是一个众所周知的受冲突影响地区，非法采矿现象普遍存在。在第一步中 我们表明，通过光学显微镜观察金颗粒的形态或通过激光诱导击穿光谱法检测汞，可以很容易地发现使用非法汞合金的合并情况，从而可以在现场进行直接检测。在第二个主要步骤中，我们证明了可以通过测量金粒种群的Ag含量并将其与具有Kolmogorov-Smirnov统计量的数据库进行核对，来高度肯定地证明所声明的黄金来源。在可以识别未知金来源的最后一步中，我们使用了（i）微量元素（铜和汞）的含量，（ii）鉴定样品中的矿物包裹体及其相对比例，以及（iii）通过LA-ICP-MS测定并结合方差的多元排列多元分析和相似度百分比分析，确定天然金晶粒的微量元素组成。这种方法可以鉴定出69％的金样品的出处。其他金矿的起源（31％）由于与其他群体的地质相似性而无法确定。我们的创新方法可以保证天然金的可追溯性，特别是通过证明已申报的黄金种群来源来保证。要解决的进一步挑战将是在其他受冲突影响地区实施这种方法以支持全球黄金供应链。