This is a piece of the first scientifically authenticated meteorite found in Michigan, known as the Grand Rapids Meteorite. It is an iron meteorite.
It was found in May 1883 by M. Clancy, a contractor excavating some land of the Catholic Church for building purposes.
The original meteorite had a mass around 52 kilograms (114 pounds) and was somewhat pear-shaped with overall dimensions of 35 x 25 x 18 cm.
This meteorite had been deposited by a glacier at some point in the past, due to being found 0.9 meters (3 feet) below ground and wedged between two large boulders.
This meteorite shows the distinctive crystalline structure known as the Widmanstätten pattern, which is the interfingering of the extraterrestrial minerals kamacite and taenite and only occurs in meteorites.
The Widmanstätten pattern forms when a rock is heated to very high temperatures and then cooled very slowly, allowing two different alloys of nickel-iron to crystallize at different rates.
The Widmanstätten pattern is only visible when a meteorite is cut, polished, and etched with a mild solution of nitric acid.
This specimen is on long-term loan from the Field Museum in Chicago.