Iron concretion that traces negatively in the form of a (fragment of a) musket or iron bolt / rod in concretion from the wreck of the East Indies' t Vliegend Hart. from a print of a musket or iron bolt / rod. Originally the object was probably made of iron or other metal. Concretion; Dutch East India Company; 't Vliegend Hart (ship); c. 1700 - c. 1735; concretionary stone; h 9.5 cm x w 5 cm x d 3.5 cm x h 5.5 cm x w 4 cm x d 2.5 cm x h 5 cm x w 4 cm x d 1.5 cm