The solid state transformation of chitin beta into chitin alpha under the influence of aqueous HCl of increasing concentration was investigated in the case of highly crystalline beta chitin microfibrils isolated from the vestimentiferan tube of Tevnia jerichonana. With acid strength below 6 N, the chitin microfibrils remained un-affected. With acid strength between 6 and 7 N a total decrystallization was observed when the samples were immersed in the acid solution. When the initial beta chitin was washed, crystals or one of their hydrates was restored, but the initially large microfibrils of chitin became split into a series of parallel subfibrils of much smaller diameter. With acid strength from 7 N to 8 N, decrystallization was also observed but it was accompanied by a substantial cutting and dissolution of the chitin chains. These smaller chains recrystallized in epitaxy on the remaining beta chitin microfibrils in a subsequent washing step. In this case, the recrystallization led to morphologies resembling those of shish kebab where the "kebab" overgrowths consisted of a chitin spindle-like crystals organized in epitaxy on the underlying beta chitin microfibrillar remainder. When acid strengths of 8 N and above were used, the sample recrystallized exclusively as a chitin upon washing. As opposed to the case where lower acid concentration was used, a total loss of the fibrillar morphology was observed with HCl of 8 N and above.