Fig. 3
From: The global variability of diatomaceous earth toxicity: a physicochemical and in vitro investigation
Backscatter images of contaminant phases in DE. a a pure calcite particle in unprocessed DE from Spain (DE_05), b a particle containing calcium silicate (very light grey) and cristobalite patches (dark grey) in flux-calcined DE from Spain (DE_06), c a clay mineral particle in an unprocessed sample from France (DE_13), d a large iron phosphate particle in unprocessed DE from France (DE_13), and e-f iron-rich patches within particles in French (DE_16) and Mexican (DE_24) calcined samples