What is going on with this mineral formation?

What types of mineral are involved?

How did this happen?

This is what is known to geologists as a schist, which is a geological formation which occurs when metamorphic rock undergoes heat and pressure, forming granular slabs of rock that have "grains" visible to the naked eye. Schists are often formation sites for gemstones such as garnet, emerald, ruby, and sapphire.

This a mica schist with garnets deposited throughout. Schists don't have to be composed of one specific mineral, but this one is largely mica.

For more information, visit:

• This artifact in the Karshner Digital Collections
• Artifact Worksheets you can use in your classroom or for homeschool
• Geology and Earth Science News and Information
• Overview of Magnetism in Gemstones
• Schist: Sandatlas