Clue

Answer

1. I am the only igneous rock that is both intrusive or extrusive. This is the first question so the answer is simple.

Diabase

2. I am extrusive and glassy. My composition includes quartz. You use me for exfoliating of course.

Pumice

3. I am plutonic, coarse, and moderately dense. And I contain more amphibole than biotite.

Diorite

4. I may be part of your kitchen counter. I am not vesicular, intrusive, and coarse.

Granite

5. I am intrusive and my crystals are large. My texture is coarser than everyone else although I’m non-vesicular like the rest.

Pegmatite

6. I am vesicular and glassy. My composition contains a fair amount of pyroxene.

Scoria

7. My density ranges from moderate to low. I come from volcanoes, am glassy, and non-vesicular.

Obsidian

8. I am the darkest, densest, most mafic igneous rock that you know. I don’t come from volcanoes and am entirely olivine, you know.

Dunite

9. I come from volcanoes and my texture is fine. I contain some quartz and am non-vesicular like most of the rest.

Rhyolite

10. I contain both pyroxene and olivine, not much more. I am coarse, dense, and pretty dark for sure.

Peridotite

11. I am volcanic and non-vesicular but that is not all. I am also glassy as my name would divulge.

Basaltic glass

12. I am very similar to another extrusive rock. We both have a fine texture but I am vesicular and it is not.

Vesicular rhyolite

13. I contain minerals that are black, white-gray, and green. I am also plutonic, coarse, and contain olivine.

Gabbro

14. I am also plutonic and coarse but I don’t contain olivine.

diorite

15. I am extrusive, fine, and non-vesicular. Unlike a similar rock to me, I always come from volcanoes.

Basalt

16. I also come from volcanoes and am especially fine but I am vesicular, possibly containing olivine minerals.

Vesicular andesite

17. I have no quartz in my composition but I have a fine texture that is vesicular in nature.

Vesicular basalt