Inlay refers to a technique in which pieces of material are set into a larger base to enhance appearance. Since inlay jewelry incorporates a variety of materials, XRF spectrometers require a smaller collimator aperture to focus X-rays on a specific area. When the aperture is large, X-rays interact with a broad sample surface, causing the spectrometer to receive signals from multiple materials. Small-spot multi-application XRF spectrometers are equipped with collimators of different aperture sizes to improve testing accuracy. The smaller aperture focuses X-rays onto a very small spot, reducing interference from non-target materials.