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tvanwho

Need Crystal Id?

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I found this rock while gold dredging last year in Indiana in a gravel bar. I didn't realize until a month ago,it is a crystal of sorts ,white and dark blue and a black splotch ? It is a double crystal,Indian head penny for size comparison against a chunk of coal I found in another creek. Have been told it might be a Blue Sapphire crystal or Blue Beryl Crystal? Maybe Chris Ralph will know the answer?

Dunno how it got into an Indiana gravel bar tho? Brought down by the glaciers with the gold from Lake Superior area perhaps? There was a pile of fine gold in the gravels on an inside bend of this 15 foot wide creek and numerous pretty rocks. I busted one open today and it is a Pink/white quartz inside. I guess it pays to eyeball a bit when gold hunting...I wonder if my crystal could be made into a ring or something?

Just measured a bit. The top layer is approx. 3/4 inch across the parallel flats and 5/8 inch thick. If its a sapphire, how many carats might it weigh? Should I take it to a jeweler?

-Tom

MyBlueIndiana Crystal.JPG

BlueBackindiana Crystal.JPG

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Though it's really hard to ID stuff by photos alone, my first guess is a sapphire crystal. Try a hardness test on it.

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I wonder how clear the interior is? It appear to have zoned coloration - a dark blue center?

post-1-0-76680300-1433537095_thumb.jpg

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Zoned coloration is common in sapphire. However I would expect that the interior would not be transparent at all.

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Should I have it cut open or what would you guys do at this point? How much might it be worth cut and polished vs uncut?

I think it must have been caught by the grizzly in my mini- highbanker. I use 3/4 inch square hole perforated steel vs most folks who use parallel steel bars. This stone would have slid out the backend of the highbanker otherwise.

Purely accidental find, maybe I need to rethink my gold digging operations in this creek?

What would you guys do if you realized gemstones were in your gold creek? Its all privately owned so can't use big machines.

Maybe start doing some sifting instead? baseball/softball size cobbles 1st 6 inches, then large marble size cobbles/sand/fine gold, then football size,water worn cobbles at 18 inches before my hole filled in with muddy water. 3 foot deep sandy pool just downstream of the gravel bar. I was just using a shovel at the time.

Thanks,

-Tom

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First, before you get too fired up, assuming it is corrundum, its just common corrundum - its not a gem. So cutting it is not a good idea. Gems are cut, and its not a gem.

It has a small value as a specimen because it has crystal faces. Those are what made me think corrundum / sapphire more than the color. The faces have the right angles (120 degrees) to be sapphire. I would say the specimen as is is worth maybe $5 or $10 - no more.

I know of a place near Carson City where you can dig similar material.

Did you get a number of smaller pieces in your cons? - If not, it was just a random find. As you know the glacial materials of the area have been transported many hundreds of miles.  Corrundum is a density of 4 and will concentrate with your black sands.

If it were me, I'd keep it as an interesting specimen, and then keep an eye out for more in my cons, should I perchance come across them.

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Ok thanks Chris. My rockhound friend in Arizona, has concurred that my crystal is non gem quality sapphire,not so valuable but good enough for my living room rock shelf collection anyway.

He tells me the gem must be Clear to have any real value altho the size is unusually large and I've never heard of sapphires being found in Indiana,only tiny diamonds.

I guess I could always send my photos to the Indiana Geological Survey for a little notoriety..

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We have this little book put out by the Indiana Geological Survey.It is called Gold and Diamonds in Indiana.

Mostly written in early 1900's by old timers. I've read it numerous times, but this last time reading it , some things really caught my eye.

Some of these old guys ,using no more than large steel gold pans, no sluices or dredges, got 10-14 ounces of gold in a few months of work in Indiana creeks and also recovered a few diamonds. I just realized how big the stones they got were, between 2-5 carats and gem quality, would be similar to  the better ones they find at Crater of Diamonds state park in Arkansas.

But I have yet to hear of anybody in modern Indiana , using motorized equipment, finding any gemstones at all, besides the sapphire I got by accident. I wonder why ?

   I hope to get back to the creek where I got that sapphire this summer, see if can find another where my map dowsing likes, at a sharp  bend in that creek with what looks like red glacial till dirt there too. Red dirt is good in Indiana too,can be loaded with iron,gold, copper.

It really helps to use Google Earth/ToolBar/ Views/Historical Imagery. Sometimes you can find older aerials taken in late winter/early spring, and be able to see the streams vs   heavy tree cover in more recent images where you cannot see the stream at all. I was browsing another creek and came across a tall blue/ gray clay creek bank like 150 feet long x 30 feet high and at the waterline, there are heavy reddish layers-IDEAL for glacial gold. Unfortunately, that spot is owned by a local university and they don't like prospectors. ( And the worst part is, I was actually in that creek 5 years ago , sluicing, when a group of us did get permission BUT I did not know at the time about Google Earth and the Historical Image Views ,otherwise I would have headed directly to this spot and dug like crazy!! ) 

-Tom

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I think you really need to do a hardness test though before drawing any final conclusions because it could be a few different things. It looks more like beryl to me than sapphire, but impossible to tell from a photo it could easily be either of them. Also, it should be notably heavier than a piece of quartz in your hand if it's sapphire, beryl not so much.

Either way if it's blue beryl or sapphire then it's collectible even if not gem quality. It has good crystal structure and it's twinned. Also, location is everything, even though Indiana is likely not the source, a collector there may be willing to pay more for it because it was found there. I'd say it's a $50 piece anyways, especially to the right person, maybe even double that.

Some of the common black tourmaline I found was selling for a fairly decent price just because it was from a completely unknown location. You'd be surprised (as I was) how many people collect very specific types of gems/minerals and try to fill their collections with all different type locations - sometimes the location is worth more than the sample...especially if it's rare and you have proof of where it came from.

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