Unknown Material Identification: Cosmetically Treated Hair

A Cosmetic Appearance

(An unknown sample, viewed under a stereo microscope.)

Our laboratory received an unknown, fibrous sample. The questioned material was black and thin, with a streak of fine, pink particles adhering to one side. Examination under polarized light microscopy (PLM) revealed that the black material was a dyed animal hair fragment.

(A cross section of the black material viewed under a polarized light microscope).

Further analysis by energy dispersive x-ray spectroscopy (EDS) in a scanning electron microscope (SEM) confirmed that the black material contained scales, characteristic of hair.

(The sample viewed in an SEM.  The red box shows the scales of the black animal hair.  The unknown pink particles are seen on the left.)

Elemental and chemical analysis of the pink material by EDS and Raman microspectroscopy revealed it to be composed of pigment sized particles of bismuthoxychloride, rutile, and talc. The combination and size of these particles suggested the pink deposit was a cosmetic product. The presence of these pink particles on a fragment of animal hair allowed us to conclude that the sample probably originated from a makeup brush.

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