What is a Rock?

The word rock means different things to different people. As with many words, its scientific meaning is different from many of the meanings used in everyday language, so lets start with a short video on the scientific definition of a rock.

Identifying Minerals

A few common minerals.

With nearly 3000 different known minerals, you might think that identifying mineral specimens would be difficult. Actually, it is usually fairly easy. Many of those 3000 minerals are very rare, only found in very limited areas. If you can learn to identify twenty or thirty of the most common minerals, you will be able to identify most of the specimens that you are likely to find.


These are the crystals that I grew with my Quick, Easy Crystals activity. They are composed of magnesium sulfate. Why is magnesium sulfate also known as Epsom Salts?