The Museum and Sea Center are closed until it is safe to reopen, but we are working hard on our summer Butterflies Alive! exhibit and look forward to welcoming you soon!

Identification of rocks

I have no idea what these rocks are.  I need help in identifying.

Linda Schmidt, Whitewater, Kansas - November 9, 2019

Curator Response

Hi Linda,

We can’t be 100% sure without seeing these in person, but here’s what we can say based on these photos: The large rock in the foreground of your photo of many rocks is a mica schist. The rock with the crystal-lined cavity inside it is by definition a geode. The smaller rock with reddish-brown outer layers and a milky white (maybe chalcedony) fill— second from the left in the one picture and upper right-hand corner in the other—is perhaps what we’d call a thunderegg.

Stay curious,

Dibblee Collection Manager of Earth Science Jonathan Hoffman, Ph.D.

Nature Education Manager Sabina Thomas, Ph.D.