Type of Minerals

Crystals of the mineral Pyrite from Peru Click on image for full size (124K JPG) Courtesy of Corel

So far, over 2000 minerals have been found, and every year new ones are discovered. That's a lot of minerals! Don't worry! You don't need to know them all to be a rock hound. In fact, only a few dozen are common within the rocks of the Earth's crust. That means the rocks in your backyard probably have common minerals in them that you can identify.

Minerals are divided into different groups based on their chemistry.

Silicate minerals
The most common mineral group on Earth is the silicate minerals, which all have the elements silica and oxygen as their main ingredients. Most silicate minerals form when molten rock cools, either at or near the Earth's surface or deep underground.

Non-silicate minerals
There are many different groups of other minerals that are known as non-silicate minerals. Some of these groups form when magma cools, while others form when water evaporates away leaving mineral crystals behind, or when other minerals decompose.