Perhaps it would be good to note that certain soils tend to produce certain color patinas so some issues are commonly found with a particular color and rarely found with others. VF Earthen Patina Constantius II Spearing rx. AE3 Patina can be combined with hard earth deposits that produce an attractive contrast. The example loses points for the scratches on the portrait. aVF Thick Patina Julia Domna Ceres rx. A hard even patina can be ruined by chipping or wear around the edges.
Collectors prefer patinas that are solid and stable.
EF Patchy silver Probus Horseman spearing rx. VF Porous Trajan as Coins without patina on the surface can show a fine texture or porosity. This is common on coins found in rivers but can also be the result of harsh cleaning. This example loses much detail to texture in the fields on the lower left half of the coin. F Severe pitting Caligula as Heavy pitting leaves major areas of erosion and severe defacement.