Cosmetic Trace Evidence
A tissue containing a faint stain was submitted to determine if evidence of a make-up stain was present. Although the tissue had been previously analyzed by another laboratory (to no avail) and only a single, barely stained area of the tissue remained, we were able to use light and electron microscopy to characterize the particles present.
Light microscopy showed the presence of a glitter particle on the tissue. In addition, flakes of mica coated in titanium dioxide and iron oxide were observed. Silica microspheres, typically used in cosmetics as a skin “softener” were also observed. The glitter combined with the mica and microspheres provided a strong indication that the stain on the tissue had originated from a cosmetic. This information, along with other evidence in the case provided sufficient information the jury to convict the defendant.
Such approaches can be used to study ancient pigments, coated papers, inks, paints, and other pigmented materials.