TD90AB3: Slightly rounded pebble, very rich in cavities and relief, with diffuse parallel aggregates and feebly defined, but present, crystalline forms and included Quartz fragments.
Peixoto de Azevedo River, Terra Nova do Norte, Amazonas, Mato Grosso  Brazil

Specimen size: 1.9 × 1.1 × 0.8 cm = 0.75” × 0.43” × 0.31”