Fig. 3. TEM images showing silver sulfide nanoparticles in calcite.

a Spherical to ellipsoidal silver sulfide nanoparticles occurring as individuals or aggregates dispersed in calcite. b Aggregation of silver sulfide nanoparticles. c A representative silver sulfide nanoparticle exhibiting lattice fringes with a d-spacing of 0.222 nm. d An electron diffraction pattern for a selected area containing silver sulfide nanoparticles. e An electron diffraction pattern for the single silver sulfide nanoparticle illustrated in Supplementary Fig. 3b indicates that the silver sulfide is acanthite. Ag-S, silver sulfide nanoparticles; Cal, calcite.