Determination of Fe concentrations in individual olivine grains using an in-house compact magnetic separator

Abstract Olivine particles with different Fe concentrations were magnetically separated, and a calibration curve of them was obtained by a magnetic separator, which was designed and assembled for rapidly analyzing heterogeneous solid particles according to their variance of magnetic susceptibility per mass [= $${\chi }_{\text{m}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>χ</mml:mi> <mml:mtext>m</mml:mtext> </mml:msub> </mml:math> (emu/g)]. The system was based on a dynamical principle that acceleration of a magnetic translation initiated from an identical position in an area of a monotonically increasing field does not depend on sample mass m [g]; it uniquely depends on the intrinsic $${\chi }_{\text{m}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>χ</mml:mi> <mml:mtext>m</mml:mtext> </mml:msub> </mml:math> value assigned to the material. The olivine particles used in the experiment were tuned to a size of ~ 0.5–1.0 mm in diameter, and the resolution of identifying Fe concentrations is higher than 1 wt%, where Fe concentrations of olivine particles ranged from 0 to 10 wt%. The apparatus introduced in this study to detect Fe concentrations of olivine particles is easy to operate. It has a compact size so that it can be used in various activities to collect geochemical samples. Accordingly, the time and effort required in searching a target sample are considerably shortened both in laboratory and in field research. Fe concentrations of silicate materials are important in estimating the formation conditions of various geological materials; for example, in studying the redox conditions of the region where minerals in meteorites formed, and in estimating formation conditions of terrestrial rocks.