TIL I'm not as good at spotting different rocks as I thought.

I went hiking over the weekend and was sure I found a bunch of quartz, but when I got home and looked closer, half of it was actually calcite. I guess I was just seeing white crystals and getting excited. I tried the scratch test with a penny, and that's when I figured it out. It's a bit of a letdown, but now I want to get better at telling them apart on the spot. Does anyone have a simple trick they use in the field to tell quartz from calcite without carrying a whole kit? I really want to avoid filling my pack with the wrong rocks next time.

2 comments

2 Comments

aaron_flores847d ago

Yeah, a pocket knife blade works for that scratch test too.

quinnb367d ago

Hold up, you tried the scratch test with a penny? That's actually pretty smart for a quick check! Quartz is way harder than calcite, so it should scratch glass easily. Calcite will scratch with a copper penny though, which is why it worked. For the field, just carry a small piece of glass or a steel nail to test hardness. That way you don't end up with a bag full of calcite again, lol.