Tbh, I spent 3 days trying to figure out if a rock I found was basalt or andesite before I gave up and took it to the university lab.

Honestly, I was convinced my hardness test kit and hand lens were enough, but the fine-grained texture and lack of obvious phenocrysts had me second-guessing everything for 72 straight hours, so what's your go-to method for telling those two apart in the field?

3 comments

3 Comments

val1721mo ago

Been there. I just gave up and licked it. Basalt tastes way more metallic than andesite to me. It's weird but it works.

josephc591mo ago

Lol that's hardcore. I could never bring myself to actually lick a rock. I just carry a little bottle of water now to do the streak test.

john_singh23d ago

Tried water, just licked it anyway.