A creek find shook my trust in simple scratch tests

I was sure my method was good, using a steel nail and glass to test rocks. For a long time, I'd call anything scratching glass quartz or harder. Then I picked up a stone from a creek that passed the test. But the way it broke was different, and it turned out to be a feldspar. Now I hear two sides: some say scratch tests are must-dos, others say they trick you. I'm thinking of using more checks. Has anyone else had a rock fool their usual way?

4 comments

4 Comments

eric_schmidt1mo ago

Scratch tests can totally fool you sometimes. Your feldspar story shows they're not perfect on their own. Gotta use a couple different checks to be sure.

young.caleb1mo ago

Actually scratch tests are pretty reliable if you know what you're doing, @eric_schmidt. Most folks in the field get good results using just that one method before moving on. Why make things more complex than they need to be?

mason.sandra1mo ago

@young.caleb knows his stuff, scratch tests get the job done without overcomplicating things.

the_paul27d ago

That feldspar story is a perfect example. Scratch tests give you a good starting point, but they can definitely lead you wrong. I've started doing a quick streak test too just to be safe.