Posted: Jul 05, 2017 16:40 Post subject: Need help to identify a rock
While I was walking in a beach, I saw these 2 rocks and picked up. They are very beautiful. One has black, blue, purple and gold colors, other one is black and gold. I did a bit go ogling and they might be covellite? These are not very hard and easy to scratch them. Any help is appreciated.
Posted: Jul 05, 2017 16:59 Post subject: Re: Need help to identify a rock
Sorry but you need to give us more information before we can help you. Please read Asking: "What is this? / Where is it from?" and provide us with some basic information about the specimen as well as at least one sharp photograph.
In case you need even more help you can use this fine web page from Minsocam.org, the Mineralogical Society of America.
Posted: Jul 05, 2017 18:05 Post subject: Re: Need help to identify a rock
I see from the video why you thought it might be covellite. But that would be pretty much unheard of, as a beach stone (especially in Massachusetts).
As per what Matt said, please do look at our identification guidelines under the site guide, though I suspect, you'll have a hard time getting any measurable/definitive properties. Try to make your best judgement as to... hardness, density compared to "average" rocks, etc.
Some of my thoughts/guesses: mafic (iron-rich) coarse-grained igneous rock with cleavage grains of iridescent pyroxene and/or labradorite feldspar; some kind of slag; silicon carbide (unlikely--it's very hard, wouldn't get rounded)...
Posted: Jul 06, 2017 05:25 Post subject: Re: Need help to identify a rock
Hi, Microboston, list
As said, without more info that being found in a beach, few could be said....
But, to me eyes, looks as a piece of man made silicium carbide (carborundum), let in beach and there abraded/tumbled to look as it looks now.
For a covellite, I am pretty sure it is not. Covellite is very soft, and a copper sulphide with water, oxygen and salt (being in a beach, plenty of all...), well, very quickly copper sulphate,or copper chloride, both extremely soluble in water, so, altered and gone.....
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