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The Universe at Your Fingertips 2.0 DVD from the Astronomical Society of the Pacific is in our online store, filled with Earth and space science resources.

Pick a Postcard - Rocks, Minerals and Fossils

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
Windows to the Universe Image

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.
Windows to the Universe Image

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF