These three crystals of the mineral quartz show how the same type of mineral can have different colors!
Windows to the Universe
Amethyst crystals from Brazil
Courtesy of Corel Photography
A fossil brachiopod!
Oklahoma University/Earth SceinceWorld Imagebank
This photograph shows several crystals of the mineral, calcite. The crystals in this example are shaped like pyramids. Therefore, the crystals are known as "dogtooth".
Courtesy of Corel Photography
Orthoclase feldspar
Gypsum
Windows to the Universe/L.Gardiner
This is a photograph of the mineral, hematite. Hematite contains lots of iron. The chemical formula for hematite is Fe2O3.
Windows to the Universe original image
Crystals of the mineral Pyrite from Peru
Courtesy of Corel
These two examples show the shape of individual quartz crystals.
