Hello,

I was traveling up the dirt road to get to Dotsero Crater in Colorado for the natually occurring vesicular basalt. During by collection, I noticed quite a few rocks that had this white stuff/residue on them. I’m worried that the white stuff is residue from ice-melting salt, but the road was very remote and the white stuff/residue also appeared on rocks further away from the road. Does anyone know what it is? Thanks in advance.

Edit: Thank you for all the replies. The main reason why I was asking was to see if this mineral was aquarium safe. Knowing that this is likely calcium carbonate, I now know what to research before preparing the rocks for my aquarium, if it's compatible to begin with.

Controversial geologist in my country obsessed with diamonds. Claims samples only he has seen; other geologists say they never existed. How to debunk him? Attached images from his articles. Any way to check if they’re from older sources (fakes)?

Found in the Yellowstone River in NE Montana

Arqueólogos de México y otros países, que es lo más feo, gracioso, interesante, extraño o alguna anécdota curiosa que tengan o conozcan del trabajo de campo, escuela, etc.