Introduction to the Rock and Mineral Hall: The Rock and Mineral Hall mainly exhibits rock and mineral specimens. Rock specimens are displayed according to three major rock types: igneous rocks, sedimentary rocks and metamorphic rocks. Mineral specimens are divided into five categories based on chemical composition and crystal structure: natural elements, sulfides and similar compounds, oxides and hydroxides, oxygenated salts and halides. Mineral specimens are arranged according to the above categories, and there are a wide variety of rock specimens with various names. There are familiar rocks such as limestone, granite, and sandstone, as well as minerals such as quartz and feldspar, as well as many unfamiliar types of rocks. The hall also displays precious mineral specimens collected from the Qilian Mountains presented by Premier Wen Jiabao. A total of 1,071 rock and mineral specimens and 100 pictures are exhibited in this hall.