bauxite, manganese, talc and marble. Minerals of note are: gold, hematite, dolomite, tourmaline, pyrite, muscovite, topaz and imperial topaz. The imperial topaz is a stone only found in Ouro Preto. Soapstone handicraft items are a common souvenir among tourists, and can be found in many shops in the town centre and street fairs. Jewelry made of local precious and semi-precious gemstones (such as hematite) can also be found for sale. The University and the fraternities Ouro Preto is also a university town with an intense student life. The Universidade Federal de Ouro Preto (Federal University of Ouro Preto or UFOP) has approximately 10,000 students in the city. Many of them live in communal houses that are somewhat similar to fraternity houses as found in North American colleges. These communal or shared houses are called repúblicas, 66 of which are owned by the university, called repúblicas federais, and 250 are privately owned (repúblicas particulares). The repúblicas system of Ouro Preto is unique in Brazil. No other university city in the country has exactly the same characteristics of the student lodgings found there. It shares traits with the repúblicas of the Portuguese University of Coimbra, where the tradition originated. Before universities were founded in Brazil, Coimbra was where most of the rich students who could afford an overseas education went to. Each república has its own different history. There are repúblicas in which the freshmen, also known as "bixos" (misspelling of "bichos", Portuguese for "animals"), have to undergo a hazing period, called batalha (battle), before being accepted permanently as residents of the houses. The final choice of the freshmen, called escolha, has to be unanimous among the senior students of the house. The Museu Mineralógico da Escola de Minas (Mineralogy Museum) can be of special interest to visitors. It belongs to the UFOP's School of Mining, which opened its doors on 12 October 1876. The museum is located at the Tiradentes Square No. 20, in the town's historical center, and contains a rich assortment of minerals on display, including precious and semi-precious gemstones and large crystals. Security is tight, however (for example, no cameras are allowed), due to the incalculable value of the gemstones and ores on display. Tourist attractions Ouro Preto is a major tourist destination, for its well-preserved colonial appearance with baroque architecture and cobblestone streets. Churches The city contains numerous churches, many known for their religious art and baroque