Very often there is the task to distinguish between different levels of purity of gold. In particular the separation between 99.5 and 99.9 % is important for different applications. The effort for purification is higher for the pure Gold but the material value is not very different. Because Gold is used very often in jewellery and the pieces of jewelry are small and filigree it is necessary to analyze also only small area of the specimen. If the analysis is performed non-destructive with XRF a p-XRF instrument is required that concentrates the excitation radiation to areas down to 0.3 mm. The size of the analyzed area has an influence to the analytical result - both due to the collected intensity and an averaging for slightly non-homogeneous samples in case of larger analyzed area. These influences are examined in this report.