mr dahl 's wife , marguerite dahl , confirmed on tuesday that her husband of 40 years died march 23 of chronic obstructive pulmonary disease .
his rocks , which formed a brief but remarkably successful craze for several months in 1975 , has died aged 78 in southern oregon .
gary dahl , the creator of the wildly popular 1970s fad the pet rock , has died at age 78 in southern oregon .