So, I took these to a gemologist. What she old me was surprising.

wondertuckian · Jul 15, 2015

So, I took these to a gemologist. What she told me was surprising.

So, I dug this rock up a while ago, and it's been at the edge of my driveway for a while. Got to looking at it the other day and something just didn't look right. I had thought the small crystals in the rock were quartz, but upon closer inspection, there are some that seem to be octahedrons. So, I took it to a local jewelry shop and the gemologist put one under a microscope and said she thinks it might be opal. So, I asked her if she'd ever heard of opal in the area and she asked me where I got this from.
Me."My backyard."
Gemologist. "Well, it can't be opal, then."
Me."Well, what is it?."
Gemologist. "I don't know."

So.......what do you guys think?

Sorry Thread title should read: "So, I took these to a gemologist. What she told me was surprising."
not: "So, I took these to a gemologist. What she old me was surprising."

stdenis_jd · Jul 16, 2015

Anything else u can tell us like hardness, SG, streak color?

These could be several different things like fluorite, calcite, Opal, etc...need. more. Input. :-D

G Freeman · Jul 16, 2015

wondertuckian said:
So, I dug this rock up a while ago, and it's been at the edge of my driveway for a while. Got to looking at it the other day and something just didn't look right. I had thought the small crystals in the rock were quartz, but upon closer inspection, there are some that seem to be octahedrons. So, I took it to a local jewelry shop and the gemologist put one under a microscope and said she thinks it might be opal. So, I asked her if she'd ever heard of opal in the area and she asked me where I got this from.
Me."My backyard."
Gemologist. "Well, it can't be opal, then."
Me."Well, what is it?."
Gemologist. "I don't know."

So.......what do you guys think?
View attachment 1187976 View attachment 1187977 View attachment 1187978 View attachment 1187979 View attachment 1187980

Sorry Thread title should read: "So, I took these to a gemologist. What she told me was surprising."
not: "So, I took these to a gemologist. What she old me was surprising."

Why would it not be Opal because you found it in your back yard. Another opinion would be a thing to consider.

ARC · Jul 16, 2015

Welp they are wrong...

Stone on far left in pic with the penny is a diamond :P

ARC · Jul 16, 2015

Just kidding btw... :P

Sure looks like one on the raw.

wondertuckian · Jul 16, 2015

As to the hardness of the stone, it will put nice deep scratches in quartz. I have an extra piece of polished granite from when my kitchen countertops were installed that I checked on. I don't have anything that's really hard enough to check the streak color, unless you think a diamond knife hone would work? When I say it was in my backyard, I mean it was in the yard, 8-10 feet down, in an old stream-bed. The loose crystals in the pics were "eroded" from the matrix in a rock tumbler, including the one with the penny that "looks like a diamond". And that point was facing out when I started tumbling it. The gemologist did say she didn't believe it was quartz, based on the octahedral form, and after I mentioned that I extracted it with a rock tumbler said that it probably couldn't be opal, either, but, didn't want to speculate any further. She said she needed a flat polished surface to check further. All in all it was helpful in that we did at least eliminate a few possibilities.
Sorry to ramble, hope that helps.
And if any of you guys have a way to test it to say for certain what it is I could maybe put a couple in an envelope & mail it.

wondertuckian · Jul 16, 2015

I was also wondering if you'd know of a better way of extracting these crystals. Even though it doesn't really seem to be rounding off the points or polishing them to any great extent, some of them have been broken by the process. I'd like to avoid that, if possible. Or, would it be better, assuming I can get this identified, to turn it into specimens? That piece in the picture is just a smaller fragment of what was a 1 pound rock.

stdenis_jd · Jul 16, 2015

Topaz is a good possibility

wondertuckian · Jul 16, 2015

Hadn't considered topaz, never heard of any in my neck of the woods. Which, btw. is NE Illinois. Doesn't mean it aint here, just never heard of any. :dontknow:

I do know that there are diamonds nearby, the six-pack lamprophyre in Kenosha, WI is about thirty miles NE of me.

wondertuckian · Jul 16, 2015

ARRC said:
Here is one that is fresh from the ground...

View attachment 1188144

Invalid attachment?

hvacker · Jul 16, 2015

wondertuckian said:
Hadn't considered topaz, never heard of any in my neck of the woods. Which, btw. is NE Illinois. Doesn't mean it aint here, just never heard of any. I do know that there are diamonds nearby, the six-pack lamprophyre in Kenosha, WI is about thirty miles NE of me.[/QUOTE

A lot of rocks in NE Ill were moved there by glacial activity which is why you have so many rock quarries. They might have come from way up North.

wondertuckian · Jul 16, 2015

ARRC said:
Click it.

This is what I get when I click it.

wondertuckian · Jul 16, 2015

hvacker said:
A lot of rocks in NE Ill were moved there by glacial activity which is why you have so many rock quarries. They might have come from way up North.

Yeah, you'd think with all that there'd be more rock shops around. The gemologist suggested going to one. Closest one is 35 miles away. Just got back. What a waste of time. The kid working there was rude and clueless.

Eu_citzen · Jul 17, 2015

Get a geologist to look at it. Doesn't look like diamond to me.

Spinel is also possible.

wondertuckian · Jul 17, 2015

Eu_citzen said:
Get a geologist to look at it. Doesn't look like diamond to me.

Spinel is also possible.

Hadn't really considered spinel as most of the crystals are colorless, or nearly so.

DeepseekerADS · Jul 17, 2015

wondertuckian said:
This is what I get when I click it.

View attachment 1188172

Same here

hvacker · Jul 17, 2015

wondertuckian said:
Yeah, you'd think with all that there'd be more rock shops around. The gemologist suggested going to one. Closest one is 35 miles away. Just got back. What a waste of time. The kid working there was rude and clueless.

Geologists have said the Ozark mountains extended into Ill but were ground down by the glaciers. Traveling into Mo and Ark the rock shops abound.

wondertuckian · Jul 17, 2015

Had to make a run down to Maywood, IL today, stopped in at the Lizzadro Museum of Lapidary Art in Elmhurst. Their gemologist spent some time looking at these crystals and came to the conclusion that they are probably zircon, but recommended taking them to a place in Chi-town just to rule out a slight chance they're diamonds. It was definitely worth taking a couple mile detour to stop in there, just wish I'd had more time to wander around & check it out.

wondertuckian · Jul 18, 2015

Well, I think I've come up with a reasonable plan of action, now that I've narrowed this down to zircon or diamond. I'm going to extract as many stones as I can in my rock tumbler and once I have enough loose stones, I can check to see what the specific gravity is. Hopefully we'll know more in a week or so.

Eu_citzen · Jul 19, 2015

wondertuckian said:
Hadn't really considered spinel as most of the crystals are colorless, or nearly so.

I think Spinel can be colourless. Hardness (if tested correctly) and crystal shape could fit.

So, I took these to a gemologist. What she old me was surprising.

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What caused this pattern of weathering?

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