I've been calling that rock in my yard 'granite' for years, and my kid's science fair project proved me wrong

My daughter needed a rock for her 4th grade project, so I pointed to the big speckled one by the garden. She took it to school, did the scratch test with a steel nail (it left a mark), and brought home her board. Right there, in her neat handwriting, it said 'GABBRO'. I felt pretty silly. I guess I just assumed all the gray, sparkly stuff around here was granite. Has anyone else had a backyard rock totally surprise them?

4 comments

4 Comments

nelson.gavin14d ago

Granite and gabbro are basically the same thing for most people. The science fair project is cool, but you weren't really wrong to call it that.

theajohnson14d ago

My 7th grade science teacher marked me down for saying "lava" instead of "magma" on a volcano diagram. It's the same basic idea, just where it is. @nelson.gavin is right, most folks just see a big gray rock. Getting the spirit of the project right matters way more than the perfect textbook word.

casey81814d ago

I read a geology blog that said gabbro is just granite's heavier cousin with less quartz. Nelson.gavin has a point about them being basically the same for yard talk. Your kid's project nailed the detail most of us would miss.

the_robert5d ago

Wait, isn't gabbro way darker than granite though? Like granite has a lot of quartz so it's lighter. That's a pretty big difference for a rock nerd, lol.