What is ridgeology primarily the study of?

Ridgeology is primarily the study of the uniqueness of friction ridge structures found in fingerprints. This discipline focuses on the patterns and characteristics of the ridges, furrows, and other details present in skin impressions, which are crucial for identifying individuals. The unique formations of these ridges, including their patterns, shapes, and configurations, allow forensic experts to distinguish one person's fingerprints from another's. Each individual has a distinct arrangement of friction ridges, which makes this aspect of study vital for forensic science and criminal investigations.

While the other options involve important aspects related to fingerprints—such as their chemical composition or biological origin—they do not capture the essence of ridgeology, which is centered on the characteristics and uniqueness of the ridge patterns themselves. Understanding this uniqueness is essential for accurate fingerprint analysis and comparison in forensic applications.