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Are these faceted stones genuine?
  
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stoner




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PostPosted: Dec 30, 2018 06:00    Post subject: Are these faceted stones genuine?  

Hello everybody, greetings from Czech Republic.
I have problem... The story of these cut stones is such that it is a soil finding from the house where around 1920 lived a jeweler. The new buyer found these on the ground behind the beam when renovating the house ... Someone said it was only glass; how can I find out and possibly not destroy the stone? Still, I was just wondering why someone would have kept a glass of glass behind the woods? :-) I will be grateful if somebody would advise me to determine it. Or what stones could they be? Čevený - garnet? white - zircon? black - tourmaline? and yellow?
This finding has caused more questions than answers ....

If it will important I will try make better photos, but stones are only some maybe 2 - 3 mm



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alfredo
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PostPosted: Dec 30, 2018 06:58    Post subject: Re: Are these faceted stones genuine?  

Determining the identity of cut gemstones, when you have them physically in your hand, is not an easy task. It requires a microscope, and often several other technical instruments too (refractometer, dichroscope, berman balance, shortwave and longwave lights, etc...), PLUS experience. To do this from a photograph, without having the gem in hand, is utterly impossible. Any opinions expressed on the topic from just these photos would be just hot wind. Best take them to a professional to check... although that might cost some money. Sorry to be a wet blanket, but I'm just being realistic.
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Peter Megaw
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PostPosted: Dec 30, 2018 07:18    Post subject: Re: Are these faceted stones genuine?  

Alfredo is right...to determine what they are if genuine requires an expert with equipment.

That said, there are a couple of things you can do to show they are not genuine...given that the most common substitute for gemstone is glass. Get yourself a magnifying glass...at least 10x...and look at them closely for bubbles. Glass often contains many tiny round bubbles...real gems never do. Another thing you can do is look at them in water...best in a clear glass tube so you can look at them with your magnifier. Take a piece of opaque paper and cut a narrow slit in it and use this to mask your light source so just the tube is illuminated. This makes the bubbles easier to see and if you back light them

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Peter Megaw
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PostPosted: Dec 30, 2018 07:24    Post subject: Re: Are these faceted stones genuine?  

Backlighting them in water will also reveal inclusions, color centers and other imperfections that one expects in natural gemstones. Glass wont show these features. Another thing illuminating them in water will do is accentuate differences in index of refraction. Glass has a pretty low and constant index (unless it's lead crystal) so your stones may all look pretty siimilar despite the differences in color.
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Peter Megaw
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PostPosted: Dec 30, 2018 07:32    Post subject: Re: Are these faceted stones genuine?  

Finally, your stones are all cut in an ususual way...with two points. This is not how most gems destined for jewelery are cut. Further, they look sharp and virtually identical in size...another unusual feature suggesting they were intended for a common purpose...one that was perhaps not fulfilled? Like being drilled for beads.

The Czech Republic has been the source of high quality cut glass beads for a very long time...

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SteveB




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PostPosted: Dec 30, 2018 08:43    Post subject: Re: Are these faceted stones genuine?  

Peter’s points are correct. I’d bet these are worthless cosmetic jewellery fillers, not genuine gemstones. Take them to a real jeweler and pay to get them appraised. As has been said it can’t be done with photos. It take tools, knowledge and skill to identify gemstones once cut. A jeweler is your only option. Even if the story of them found at a jewelers place was true (you haven't any proof) it's more likely evidence these are worthless paste. Jewellery is a trade requiring skill and care, no jeweler would ever drop a single valuable stone, doesn’t happen.
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stoner




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PostPosted: Dec 30, 2018 09:03    Post subject: Re: Are these faceted stones genuine?  

Thank you to all,
I will try watch them in water, but I think its a glass too... And sizes are differents, I have only thats from photos, but all what was founding was around 10 pieces.
Suppose it's glass. If I decided to sacrifice one piece. Is there any destructive method of distinguishing stone from glass? For example, chemical ...?
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Peter Megaw
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PostPosted: Dec 30, 2018 11:46    Post subject: Re: Are these faceted stones genuine?  

If this is just glass/paste, as seems most likely there is little reason to invest money in checking them out when you can be pretty sure yourself.

there is no chemical test you want to be around unless you have access to proper vent hoods and handling gear.

you could start by trying to scratch a piece of window glass with one. If it scratches it (unlikely) then its harder than glass and worth paying to have tested. If it doesn't scratch glass...and doesn't show damage itself...it probably is glass.

You could also put it in a flame (gas stove, crème brulee torch) and see if it "fire polishes" Heating glass to red hot will cause sharp surfaces to go smooth, so the edges between faceted faces should get rounded

You can also break one...glass breaks with conchoidal fracture surfaces (look it up) many gem minerals (not all) cleave, leaving smooth planar surfaces. If you have cleavage there is no way this is glass

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stoner




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PostPosted: Dec 31, 2018 09:48    Post subject: Re: Are these faceted stones genuine?  

Thank you very much for your knowledge and have a nice New Year... for everybody :-)
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Riccardo Modanesi




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PostPosted: Dec 31, 2018 12:19    Post subject: Re: Are these faceted stones genuine?  

Hi Stoner! If you start photographing inclusions you can see by microscope, it could be a significant datum.
Greetings from Italy by Riccardo.

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Hi! I'm a collector of minerals since 1973 and a gemmologist. On Summer I always visit mines and quarries all over Europe looking for minerals! Ok, there is time to tell you much much more! Greetings from Italy by Riccardo.
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