Questions tagged [rocks]

Questions about rock types, formation, chemistry, and physics. If you just want help identifying a rock please use the tag "identification-request".

Filter by
Sorted by
Tagged with
7
votes
2answers
168 views

Recreating the rock cycle

I want to recreate the rock cycle using some item that can behave as a rock. The purpose of this is to get a point across to my students about how really there is a reason why the rock cycle is called ...
5
votes
1answer
771 views

What type of sparking stone could this be?

A few years ago, I went to a beach in the south part of Chile, specifically Lake Lanalhue, it was filled with special rocks that when you picked one up and threw it against another that you would see ...
11
votes
2answers
3k views

What is the oldest sediment?

Sedimentary rocks in Akilia or at Hudson Bay have been proposed as the oldest in the world. My question is not related to rocks, but rather to sediment while still forming sedimentary deposits but ...
5
votes
1answer
230 views

What are these tumbled colored rocks?

I've been sent these rocks by a friend, but I am truly awful at identifying them because they aren't my field at all. I know some of them, but I was wondering if you could classify them all for me so ...
11
votes
2answers
2k views

Zeolites, odor control, and the witchcraft of sunlight

Various companies offer "volcanic crystals" or "volcanic rock" available in small mesh bags for odor control. The best description I have found is that these are made up largely of Zeolites. All of ...
14
votes
1answer
219 views

How are the patterns in solid rock born

I took this photo on my vacation in Finland showing white stripes in the rock going different ways. How are these patterns born?
10
votes
1answer
761 views

What kind of coal did I find?

I found a piece of (what I believe is) coal, on Cape Cod last week. Its density is 1.43 grams per milliliter. With this information is it possible to know whether it's Anthracite, Bituminous or ...
8
votes
1answer
776 views

What is this Cape Breton rock?

What is this rock? I found it in Cape Breton, Canada
12
votes
1answer
455 views

Formation of limestone without living organisms?

Limestones are formed mostly from skeletal fragments of marine organisms. However, calcium carbonate dissolves naturally in water, so the living organisms are not the only source of it in water. Is ...
8
votes
1answer
1k views

What is this brown and white rock?

We found this rock in our backyard. Could someone please tell me what it could be?
11
votes
3answers
1k views

Identifying sedimentary rocks in hand specimen

I'm currently learning how to identify rocks in hand specimen. The initial classification into igneous, metamorphic, and sedimentary is mostly ok, but I'm having a problem with further identifying ...
15
votes
2answers
45k views

Are the processes of the rock cycle currently in dynamic equilibrium?

The standard representation of the rock cycle usually looks like this: Does each stage of the rock cycle currently balance? That is, are the various processes in dynamic equilibrium, so that the ...
6
votes
1answer
902 views

How can a non-geologist identify a rock? [closed]

I found a rock on a beach in north-east Evia, Greece. Half is light gray, and half is dark gray. There are white (or very light gray) thin lines that form swirls throughout, crossing the light/dark ...
5
votes
5answers
1k views

What type of rock is this that is light colored with greenish crystals?

I found this rock. It is probably a very common rock but could an expert please tell me what rock this is?