I Found a Rock (UPDATE: 07/07/2011 I FOUND ANOTHER ROCK)

[romeo-1]

I put the detector away today and did some rock hounding. It's pale yellow and where it is broken is as clear as glass. I don't think that it is quartz because it's crystal clear all through. I think that if it was polished you could see clear through it. Any ideas?

 

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[TheCannonballGuy]

Re: I Found a Rock

As a loooong-time rockhound, I'm fairly certain it is a quartz "river pebble." Its exterior has been rounded-off and "clouded" by abrasion from grinding agaainst other rocks in the river, over a period of thousands of years.

Your rock's broken area shows what Geologists call "conchoidal" fracture. Very few minerals exhibit conchoidal fracture, and almost all are quartz-based (SiO2, a.k.a. Silicon Dioxide). In addition to quartz and human-made glass, some other examples of conchoidal-fracture minerals are Obsidian (volcanic glass), and Chert varieties such as flint and jasper.

 

[romeo-1]

Re: I Found a Rock

As a loooong-time rockhound, I'm fairly certain it is a quartz "river pebble." Its exterior has been rounded-off and "clouded" by abrasion from grinding agaainst other rocks in the river, over a period of thousands of years.

Your rock's broken area shows what Geologists call "conchoidal" fracture. Very few minerals exhibit conchoidal fracture, and almost all are quartz-based (SiO2, a.k.a. Silicon Dioxide). In addition to quartz and human-made glass, some other examples of conchoidal-fracture minerals are Obsidian (volcanic glass), and Chert varieties such as flint and jasper.

You sound like you know what you're talking about so I'm going to agree. Do you think it could be polished and if so, is this something i can do at home? Thanks.

 

[marinedad]

Re: I Found a Rock

i think its quartz too, hardness is about 7 on the mohs scale, have you checked hardness? rock tumbler to polish or slice and polish to make cabs.

 

[TheCannonballGuy]

Re: I Found a Rock

I forgot to answer the second part of your question, and Marinedad's reply reminded me of it. Yes, quartz rates about a 7 on the Mohs hardness-scale... which means you'd need some "special" sawing-&-polishing equipment to do that at home. It'd probably be cheaper to pay a Rockhound shop to do the work for you. (Some of them offer that service for a moderate fee.)

 

[traderoftreasures]

Re: I Found a Rock

I think its clear obsidian

 

[romeo-1]

Re: I Found a Rock

I've found a lot of quartz and this seems different. I can't capture it on the camera but the rock is clear as glass. When it's wet it is clear through with no real defects or inclusions (correct term?).

I've never heard of clear obsidian so I'll do a little research on that as well...thanks all for your comments.

 

[lennon631]

Re: I Found a Rock

I am by NO means a rock hound, and there's probably an obvious reason to you pro's as to why it's not my thoughts, but what about an old lightning strike?

 

[traderoftreasures]

Re: I Found a Rock

After taking a longer look I noticed bubbles in there which mean probably melted glass. More than likely a picture tube from a burnt console t.v.
but Idk just a guess on that.

 

[romeo-1]

Re: I Found a Rock

After taking a longer look I noticed bubbles in there which mean probably melted glass. More than likely a picture tube from a burnt console t.v.
but Idk just a guess on that.

Definitely not glass...it has been weathered for a long, long time which gives it that opaqueness...

 

[goldinmypan]

Re: I Found a Rock

still waiting on hardness. can you scratch it with a knife? Does it scratch a knife blade? etc

 

[romeo-1]

Re: I Found a Rock

still waiting on hardness. can you scratch it with a knife? Does it scratch a knife blade? etc

I work at a university and I dropped it off at the geology department this morning. I should know more tomorrow.

 

[DevilDog812]

Re: I Found a Rock

my guess is that it is cullet

 

[romeo-1]

Re: I Found a Rock

my guess is that it is cullet

I don't think so...wrong context...but we'll know tomorrow.

 

[diggummup]

Re: I Found a Rock

Just replying because i'm interested to see what it turns out to be. It looks like an old chunk of slag glass to me but what do I know .

 

[trixie charger]

Re: I Found a Rock

Topaz

 

[trikikiwi]

Re: I Found a Rock

I would guess glass, but I'm keen to hear what the answer is.
Cheers, Mike

 

[The Patriot]

Re: I Found a Rock

neat piece... can't wait to see what info you get on it....

 

[Ramitt]

Re: I Found a Rock

I love a good mystery

 

[IronSpike]

Re: I Found a Rock

Nice find

The chips does have a obsidian or flint chip look.

I think its clear obsidian