The Geological Museum was founded by Robert Sayles as part of the Museum of Comparative Zoology (MCZ) to represent geology to the public, thus completing founder Louis Agassiz's vision of a complete natural history museum at Harvard. In 1977 it merged with the Mineralogical Museum to form the Mineralogical and Geological Museum at Harvard University. In the early 1990s the Massachusetts Institute on Technology (MIT) transferred for preservation its petrographic collection of 3,400 specimens, which is particularly rich in local rocks.
Unlike the minerals, which were mostly acquired by donation or purchase of private collections and individual specimens, the rock collections were mostly field collected by faculty and students. In addition to faculty research collections, it was standard departmental practice until the mid 1980s for graduate students to deposit a collection of rocks representing their thesis. Collections of hand specimens from classic geological terranes were also collected on field trips accompanying regional, national, and international meetings.
The rock collections are divided into four separate collections: igneous and metamorphic ("hard" or crystalline) rocks, sedimentary ("soft") rocks, and ores. They are organized into teaching collections and archival (research) collections. Meteorites are rocks, of course, but extraterrestrial rocks! This makes them so special that they have always been a distinct collection. The rock collections strongly reflect faculty research interests. Among the most important of the hard rock collections are those of Professors Marland Billings (1902-1996) and Reginald Daly (1871-1957). The soft rock collection is almost exclusively a teaching collection assembled by Professor Raymond Seiver (1923-2004). Ores from Andean hydrothermal deposits are a particular strength of the "mining geology" collection. It was substantially grown by Ulrich Petersen, Harry C. Dudley Professor of Economic Geology (ret.1996).