What Is the Hardest Rock on Earth?

By Staff WriterLast Updated March 29, 2020

There’s no single hardest rock on Earth. The strongest types, on the other hand, include quartz in their makeup: quartzite, quartz sandstones, rhyolites and granites, according to the MadSci Network.

While many cite diamonds as the hardest rock on Earth, this is incorrect. Diamonds are not a rock. They are a mineral. Minerals are a “naturally occurring, inorganic (not alive) solid,” as MadSci explains. They also have a crystal-shaped structure.

Rocks are a little different. They contain one or more minerals, but are not minerals themselves. Granite, for instance, is made of quartz and other minerals, often feldspar and biotite.