Photos and information about 80 common rock-forming, ore and gemstone minerals from around the world.

There are approximately 4000 different minerals, and each of those minerals has a unique set of physical properties. These include: color, streak , hardness , luster , diaphaneity, specific gravity, cleavage, fracture, magnetism, solubility, and many more.

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Native copper is an element and a mineral. It is found in the oxidized zones of copper deposits; in hydrothermal veins; in the cavities of basalt that have been in contact with hydrothermal solutions; and as pore fillings and replacements in conglomerates that have been in contact with hydrothermal solutions.

What Are Rock-Forming Minerals? Scientists have identified over 4,000 different minerals. A small group of these minerals make up almost 90% of the rocks of Earth’s crust. These minerals are known as the common rock-forming minerals.

Photographs and information for a large collection of igneous, metamorphic and sedimentary rocks. Geology.com

The two most important minerals in these deposits are iron oxides: hematite (Fe 2 O 3) and magnetite (Fe 3 O 4). These iron ores have been mined to produce almost every iron and steel object that we use today - from paper clips to automobiles to the steel beams in skyscrapers.

Luster is a physical property that can be helpful in mineral and gem identification. It can also determine how a mineral or gem can be used.

Halite is mainly a sedimentary mineral that usually forms in arid climates where ocean water evaporates. However, many inland lakes such as the Great Salt Lake of North America and the Dead Sea between Jordan and Israel are also locations where halite is forming today.

Diamond is the hardest-known mineral. However, the hardness of diamond is directional. It is hardest parallel to its octahedral planes and softest parallel to its cubic planes.