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, …

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 …

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

The best way to determine if water or ice are minerals is to compare their properties to the definition of the word mineral.

Fluorescent Minerals Fluorescent Minerals and rocks glow with spectacular colors under ultraviolet light.

This appearance often occurs on cleavage surfaces of transparent to translucent minerals that include some micas, some feldspars, and some carbonate minerals. Examples include muscovite, …

Southern California is one of the most important areas in the world for the production of gem-quality and specimen-quality tourmaline. Numerous mines over the past 100 years have also produced …

Information on over 500 minerals, complete with detailed color photographs, crystallographic diagrams, physical and chemical properties, and much more. More information, table of contents.

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 …