Introduction To Geology quiz

I was wondering about doing a short history of geology as an appendix. I'm not sure if I'd include Leonardo, though, so far as I know his musings on the subject had no effect on the development of the field, and are of interest only 'cos they show what a clever chap he was, a point which hardly needs belaboring.

I'll look around for some materials. Lyell is quite good up to people before Lyell. And I used to have a great second-hand book called Ever Since The Deluge written by some German guy, but it stopped before the discovery of plate tectonics --- which is probably why it was second-hand. But it was full of good stuff up 'til then, I wish I could lay my hands on it.

Yes, but they aren't all granite in the geological sense. People who sell cut and polished rocks call anything "granite" if it's an intrusive igneous rock, and therefore has that pleasant speckled pattern. As the WP article notes: "In building and for countertops, the term "granite" is often applied to all igneous rocks with large crystals, and not specifically to those with a granitic composition." But black "granite" isn't granite. It's gabbro or diorite or something. So for example this trade website calls this stone "granite": Specifically, it calls it "diorite black granite", which to a geologist is simply an oxymoron: if it's diorite (which it is) then it's not granite (which it isn't). Note that it looks just like the leftmost of the "various granites" in your picture, which is also really diorite.Edited by Dr Adequate, : No reason given.

Odd use of the word "just". How would you like to classify intrusive igneous rocks except by what they're made of? They don't really have any other qualities, do they?

But you notice how they have two different names? The same is true of naturally occurring minerals, e.g. aragonite is orthorhombic calcium carbonate and calcite is trigonal calcium carbonate. So when you name a mineral, you do specify its crystal system and so all its other material properties.So things like density, hardness, melting point, viscosity when molten, crystal structure, etc are either properties of the individual minerals in the rock, or a consequence of their properties; so once you've said what minerals the rock is made of, you have in fact said nearly everything about it.