 Bynesian decay is a form of efflorescence of salts formed by the reaction of acidic vapors with the basic shell surface . The efflorescence can sometimes superficially resemble a growth of mold . Although first described in the early 19th century , Bynesian decay was not well understood until almost a hundred years later . The condition is named after the man ( L. Byne ) who is best known for describing it in the late 19th century , even though he was not the first person to describe it in print . In addition , Byne mistakenly assumed that the condition was caused by bacteria , and thus the condition came to be referred to as a " disease " . 
