Rocks & Fossils

Check out our rock and fossil FAQ for smart collecting tips, information about some local rock formations, and advice about fossil eggs and meteorites.

Rock identification

Good morning,

I found a rock near where I live in Santa Barbara, and I polished it, please help identify what kind of rock it is.

Thank you.

Maria, Santa Barbara - May 2, 2023

Curator Response

Hi Maria,

Thanks for asking about this rock. It looks like chert, which consists of quartz. The fact that it's been polished makes it a little harder to confirm that it's quartz, but you could try scratching a piece of glass with it as a test. The rock should leave a mark on the glass.

If you want to learn more about local geology, you might be interested in our rock and fossil page, our mineral exhibit, and our Earth Science exhibit. All of these have examples which can help you develop your own rock ID skills.

Stay curious,

Geologist Sabina Thomas, Ph.D.