Correct Answer !
Accumulation of loosely bound mineral particles. Lepispheres occur in the dissolution zone of weathered chert artifacts as spherical accumulations of silica particles. They are microscopic features which serve to scatter light in an otherwise translucent material, thus accounting for the whitish appearance on the outer surfaces of weathered lithic materials in semi-arid archaeological settings. For an example, see "Lithic Weathering: Post-Depositional Effects of Paleoenvironments on Lithic Materials".