Figure 7. Biomimetic morphologies of mineral particles formed in soil water.

Soil water was prepared by mixing one volume of soil with two volumes of double distilled water. The mixture was autoclaved, followed by centrifugation at 1800 g for 30 min. The supernatant was filtered through a 0.2-μm pore filter and frozen at −20 °C for seven days. The resulting solution was thawed at room temperature before observation by dark-field optical microscopy without fixation or staining. Various morphologies were observed, including small, dispersed particles (A), aggregated particles (B), and large formations reminiscent of living microorganisms undergoing cellular division (C).