Lumps - Lumps are common enamel defects, which are characterised by rounded raised areas with typically a diameter between 3 to 12 mm. 
Scaling - Scaling is a common enameling defect, which is caused by contamination with materials with a higher melting temperature than enamel. 
Blisters - Blisters are a common enamel defect, which is characterized by appearance of circular holes & bubbles in a cooled enameled surface. 
Fishscaling of porcelain/vitreous enamel coatings - Fishscaling is an enameling defect, which is characterized by small enamel particles chipping off.