Showerthought: My rock ID project turned into a three week puzzle

I found this cool greenish rock in a creek bed near my house and was sure it was serpentine. Spent maybe two hours looking at pictures online, felt good about it. Then I tried to do a scratch test with a steel nail, and it just didn't match up at all. That sent me down a rabbit hole checking hardness, streak, even trying to see if it was magnetic. I finally took it to the local rock club meeting last night, and a guy there said it was probably epidote with some quartz mixed in. What's a good way to tell serpentine and epidote apart without fancy gear?

3 comments

3 Comments

ryan_carr592mo ago

Honestly, scratch tests are overrated (they can be all over the place). You were probably right the first time, that creek bed sounds like a classic spot for serpentine.

sethc122mo ago

Yeah and serpentine can look a lot like jade to the untrained eye, easy mix-up.

nathan_patel1mo ago

A hardness test cleared it up for me once.