With a spectroradiometer, remains like talc, montmorillonite, and kaolinite could be identified at a crime scene

An example: a woman is abducted, caught in a human trafficking ring, or worse. To find and save her quickly, investigators and police need every forensic tool available.

Geology, more exact: mineralogy, holds the key to one form of evidence: makeup. At Miami University of Ohio, students Jessica Patrick and Jordan Vest are unlocking this potentially overlooked but telltale clue. Their super-tool: a spectroradiometer. “Maybe the eye can’t see it, but spectroscopy can,” says Patrick.

Awarded an in-college grant for women’s issue studies, Patrick, Vest, and other students are creating a library of the spectroscopic signatures and other mineralogical characteristics of different types of makeup. Ultimately, the library will be available for police, the National Institute of Justice, women’s justice organizations, and others.

The key is to create a large enough library of the ingredients. Over the past two years, the team has been collecting and analyzing different types of makeup on different substrates. Substrates might include various types of fabric, tile, bricks, and other materials on which makeup could remain behind at a crime scene.

“Makeup is basically a mineralogical product,” points out Associate Professor Mark Krekeler, who oversees at Miami University this and other forensic mineralogy projects with collaborator Claire McLeod. Vest and Patrick say that for now their growing database is focused on powder-based makeup such as blush and foundation, which contain geologic materials including talc, montmorillonite, and kaolinite. Using the spectroradiometer, they’ve been able to detect smears containing just 0.03 grams per square centimeter of makeup. The data base will also address diversity, providing spectroscopic signatures of makeup products on different skin tones.

Makeup can help link suspects, victims, and crimes several ways. “For example,” says Vest, “if a suspect denies contact with the victim, this can be used to match makeup products (found at a crime scene) with products known to be used by the victim, perhaps found in her home.”

“Geology has broad implications and connections to everyday life. It’s important in national security,” says Krekeler. He says the team hopes to release a good initial library for public use by March 2021.

Hand-held technology is available now, and affordable drone-based hyperspectral imager should be available in a few years, enabling use directly at a crime scene investigation.

Source: Geological Society of America

Miami University, Ohio, Dr. Mark Krekeler

Jessica Patrick presented the project in an online poster session during the Geological Society of America’s annual meeting: „Forensic Mineralogy: Utilizing the Mineralogical, Textural, and Spectral Properties of Makeup in Criminal Investigations“.

Science Direct: „Trends in the forensic analysis of cosmetic evidence“

(01.11.2020, USA: 11.01.2020)