Help Identifying Rocks

Reply Sun 17 Jul, 2016 09:20 pm
Regarding the first image, I found this while walking the other day, and I'm having a difficult time identifying it. I was able to snap it in half with my hands, but I can't scratch it with my fingernail. I was able to easily scratch it with the blade of my pocket knife. It is hard to tell the color in the image, but it is translucent white and blue. It's not halite - finding this out after the taste test.

This next one is interesting (to me, at least) with the relatively large formation of quartz. I thought this might be granite, but a friend dismissed that. Your thoughts?

Thanks for your help. Take care!
- MT
Reply Mon 18 Jul, 2016 03:55 am
The first one looks like cryolite which is an Aluminum FLOURIDE. (I dont reccomend taste tests except as a confirmation test) cryolite can be poisonous if little granules break off.

It seems to have a cleavage but the pictures not too clear . If it has a cleavage and is rather soft, it culd also be a feldpar like Albite

The second one looks most like a iron rich sandstone (the descriptor would be "ferruginous")

You need to include som kind of common coin or a ruler for scale in a picture.

Cryolite was a very important ore of aluminum (it was a flux in which the gibbsite and boehmiet were extracted by electrolysis) and was first found in places like Greenland ,Russia, Norway and Iceland. In fact , its usually called "Iceland SPar"

Its also found in deposits in the Caribbean,D America and Phillipines , SOuth Asia nd minor depoaits in North Carolina Colorado and Quebec

Its becoming almost extinct and the collection prices are revealing how rare its getting.
0 Replies
mark noble
Reply Mon 18 Jul, 2016 07:46 am
Just rocks, mate - No one cares about rocks.
0 Replies

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