I. Introduction
In this study, we investigate the geomagnetic orientation preserved in a stain containing iron compounds using a superconducting quantum interference device (SQUID) magnetometer. We assume that when clothes are stained with liquid that contains iron, such as ink pigment or blood, the geomagnetic orientation is preserved in the magnetization of the stain on the clothes as it dries. This could be an effective tool for archaeological surveys or criminal investigations because, if the geomagnetic orientation is preserved in clothes, it could be compared to the local geomagnetic orientation at the location where they were discovered, to determine whether the clothes were displaced after staining. To confirm this assumption, we applied a SQUID magnetometer to observe the magnetization of the stains. This paper describes the measurement system and a proof-of-principle experiment to confirm the system's effectiveness using iron compound solution stain samples.