Museum ramps
Rocks are solid materials formed through the natural aggregation of minerals and constitute the main part of the Earth's crust. The characteristics and properties of rocks depend on the types of constituent minerals, crystal size, texture, and the conditions under which they form. Based on their origin, rocks are classified into three main groups:
Igneous Rocks:
These form through the cooling and solidification of molten material (magma or lava). If crystallization occurs deep within the Earth, intrusive rocks such as granite are produced. If it occurs on the Earth’s surface, extrusive rocks such as basalt and pumice are formed.
Sedimentary Rocks:
These are created by the deposition of materials resulting from the weathering of other rocks, the remains of organisms, or the precipitation of chemical substances. These rocks are typically layered and may contain fossils. Examples include limestone, sandstone, and shale.
Metamorphic Rocks:
These form when igneous or sedimentary rocks undergo transformation due to high pressure, elevated temperature, or chemical processes, resulting in new structures and compositions. Notable examples include marble (from the metamorphism of limestone) and gneiss (from the metamorphism of granite).
These three major groups constitute the rock cycle and demonstrate the continuous dynamism of the Earth.
Chalcanthite is a hydrous copper sulfate mineral (CuSO₄·5H₂O) typically found as transparent crystals in light blue color. It forms secondarily in arid regions and copper mines through the oxidation of copper sulfides. Chalcanthite is used industrially as a source of copper and in preparing antifungal solutions.
Pyrite, with the chemical formula FeS₂, is a common sulfide mineral known as “fool’s gold” due to its golden metallic luster. Pyrite occurs in sedimentary, igneous, and metamorphic rocks. It is used in the production of sulfuric acid and sometimes contains small amounts of gold, which adds to its economic value.
Carbonate rocks in limestone caves are primarily composed of calcite (CaCO₃). These rocks form when rainwater combined with carbon dioxide dissolves limestone and produces calcium bicarbonate. When CO₂ is released or water evaporates inside the cave, calcite precipitates as thin layers.
Carbonate deposits in caves create beautiful structures such as stalactites, stalagmites, and limestone columns. This process is extremely slow, and the formation of just one centimeter may take thousands of years. These features hold great geological significance as well as high aesthetic and tourism value.
Stalactites are natural structures hanging from the ceilings of caves. They form as calcium carbonate–rich water drips from the roof. As the water evaporates, lime deposits remain and gradually build narrow hanging tubes or cones.
Stalagmites form on cave floors directly beneath stalactites. When lime-rich water droplets fall and evaporate on the ground, calcium carbonate accumulates, creating upward-pointing conical formations. Sometimes, stalactites and stalagmites grow until they meet and form a beautiful stone column.
The Qaleh-Zari copper mine, located in South Khorasan Province near Birjand, is one of Iran’s oldest and most important copper mines. The deposit contains sulfide minerals such as chalcopyrite, bornite, and chalcanthite, which occur as veins within volcanic and sedimentary rocks. Its mining activities date back several decades, and the extracted copper is used both domestically and for export. In addition to copper, the mine also contains small amounts of gold and silver, increasing its economic value. This mine plays a significant role in supplying raw materials for Iran’s metallurgical industries.
The Azna talc mine in Lorestan Province is one of Iran’s largest talc deposits, located near the city of Azna. Talc is a soft mineral with a hardness of 1 on the Mohs scale and is used in various industries, including cosmetics, papermaking, ceramics, and plastics. The talc extracted from this mine is of high quality, and due to its brightness and purity, it is valued by both domestic industries and foreign markets. Mining activities here have contributed to regional economic development and created numerous job opportunities for local residents.
The Parvadeh coal mine in Tabas, South Khorasan Province, is the largest coal-bearing area in Iran and holds the nation’s most significant reserves of coking coal. Due to its high-quality coal and ability to supply the steel industry, the mine has strategic importance. Extraction is conducted underground and uses advanced technical methods and equipment. Multiple development projects are underway to increase annual production capacity. Parvadeh mine not only meets domestic demand but also has export potential and plays a key role in regional employment.
