Asked December 3, 2016, 12:54 PM EST

What kind of rock is this. It has a lot of shiny crystals or little diamonds on it

Harris County Texas geology

1 Response

The two samples appear to be totally different. The dark grey sample on the left could be a metamorphic rock of some sort, based on the way the texture looks. The lovely aquamarine sample on the right could be a piece of quartz. With just a little added minerals to the basic SiO2 geochemistry of quartz, it can easily change color from clear to a variety of hues. To help with identification, if you can share where you found the sample, it helps a geologist narrow down what the sample might be.

If you can take them down to an earth science department at a local university or college, they would be able to better identify what you have.

Nice rocks!