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, …

Most of Earth’s crust is comprised of a small number of minerals. These minerals are known as the common rock-forming minerals.

A small number of minerals and rocks will glow with spectacular colors under ultraviolet light. Learn how this happens.

A list of minerals in order of hardness can be a handy reference. If you determine that a specimen has a hardness of Mohs 4, you can quickly get a list of potential minerals.

The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in …

An introduction to rocks and minerals with detailed photos, description and identification information. Sponsored by the National Audubon Society, the National Wildlife Federation, and …

The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in …

The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in …

What is Amphibolite? Amphibolite is a coarse-grained metamorphic rock that is composed mainly of green, brown, or black amphibole minerals and plagioclase feldspar. The amphiboles are …