There are studies that have looked at similar preparations in mineral oil. A recent reference with abstract is below. It seems to form a good tribofilm for boundary lubrication. For copyright reasons, I can't post the manuscript. But if anyone has a specific question, I can dig through the paper and let you know what I find.
Helong Yu,Yi Xu,Peijing Shi,Hongmei Wang, Min Wei, Keke Zhao, Binshi Xu.
Microstructure, mechanical properties and tribological behavior of tribofilm generated from natural serpentine mineral powders as lubricant additive.
Wear. Volume 297, Issues 1–2, 15 January 2013, Pages 802–810.
Abstract
Surface-modified serpentine powders with an average size of 1.0 μm were dispersed into mineral base oil to improve the lubricating properties of oil, as well as to generate a thin tribofilm on the worn surface. SEM, TEM, nano-indentation and Stribeck testing were performed to study the morphology, microstructure, micromechanical properties and tribological behavior of the tribofilm, respectively. Results show that a nanocrystalline tribofilm, with a thickness of 500–600 nm, is formed on the worn surface under the lubrication of oil with 1.5 wt% serpentine. The film is mainly composed of Fe3O4, FeSi, SiO2, AlFe and Fe-C compound (Fe3C). A phenomenological model of the tribofilm generated by serpentine was developed based on the experimental results. The excellent mechanical properties, reinforced phase of embedded particles and porous structure of the tribofilm contribute to the reduction of friction and wear, especially in the case of boundary and mixed lubrication.