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How To Tell If Its A Diamond?


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Umm... I'm not sure anyone could help in a definitive way from the photomicrographs.


FWIW, the crystals look prima facie not dissimilar from natural diamonds found in mines, but they could also be something else (e.g. quartz). There is not enough detail to rule out much among the transparent/colourless minerals - of which there are dozens, and I struggle to think of any definitive "home lab" tests you could do with crystals that size.


If you are confident that because of experimental conditions the only thing that could be in there is made of carbon (plus or minus a few ppm of impurities/atmospheric gases), then I'd be equally confident that those are diamonds. Can you?


The other options (in terms of structural arrangements of carbon atoms) are lonsdaleite, which AFAIK is brown-yellow, while the crystals there seem basically colourless, or the fullerene series which however are (again AFAIK) opaque and black, so both seem to be ruled out.


Lacking more information on the experiment, some ideas on how you could proceed for ID:


Normally "foolproof" diamond ID is through measurement of hardness, refractive index and/or specific gravity, but I suspect the crystals are too small for you to perform any of these tests; if despite my concern you can, there's your solution.


Another option is to magnify the images further (by at least another factor of 10) and seeing if distinctive crystallisation signs/shapes of diamonds are present: octahedral shape, trigons on sides etc. However, I'm not sure that in "shocked" diamonds (originating from sudden and short compression) any of these would be present.


Thirdly, you could try exploiting the fact that diamonds are extremely lipophilic (they don't get dissolved, but fats stick to them very strongly), and seeing if the crystals stick more to fat than a series of other, known crystals of similar size and shape.


Finally, and most expensively, but possibly within easy reach of a university lab, is x-ray diffraction and spectroscopy, where you could identify composition AND confirm cubic lattice structure at the same time.


Hope this is of some help. And if you can, please let us know more about the experiment and what you are trying to achieve.


Late edit - added a few more bits of info after research.

Edited by davidelevi
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Thanks everyone. Sorry for the late response. All suggestions was helpful. About the experiments will share if there will be any positive results, until then no point to do it.

On the images below is 0.1 karat diamond. Please grade the quality from 1 to 10 scale. I'm trying to learn much is possible about the diamonds. Thanks again.









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I'm not sure what you mean by "grade quality from 1 to 10". Quality of what? Colour? Clarity? Transparency? Cut? Visual size? The diamond's overall beauty? "Value for money"? On what scale? 1-10 means nothing without defining what each step means. Is "6" good, adequate or poor? Based on what criteria and metrics?


FWIW, it's a pretty highly included diamond. My guess is that GIA would grade it at least I1, more likely I2 for clarity. It seems to be pretty cloudy/non-transparent either, but it could be an artefact of the photos. Colour cannot even be guessed at, and the same goes for cut quality.

Edited by davidelevi
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By and large the objective gem-related factors driving price are:


Size (weight)

Cut and proportions

Clarity + visibility of inclusions

Transparency (not the same as clarity!)



Finish (to some extent captured under cut too)


In terms if how these things affect price, take a look here: http://www.diamondreview.com/diamondsit's free, it's anonymous and it has the price of over 500,000 diamonds with a pretty comprehensive set of filters to figure out what drives what.


"value" is a subjective evaluation. Some people find greater value in a 3 ct rock of indifferent cut, tinted colour and relatively low clarity than in a very small (but pink) diamond; for others the reverse is true. Neither is wrong.


The other thing to understand - which is not a "gem property", but is important nevertheless - is that the commercial conditions matter. I would include:


Lab report(s) and other 3rd party information

Type and location of vendor


Sales T&C, including after-sales service and offerings



as a minimum to look at "price" sensibly.

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We recently did a software upgrade, and the links along the top got messed up, including the search box and the forum rules link.  Working with software vendor on a fix...


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  1. Check the ‘Read-Through’ effect:

    If the stone is loose or unmounted you can turn it upside down on a printed piece of paper. If you cannot read the text through the stone it may be a real diamond. If the letters are visible, it is probably not a genuine diamond. This test works best with properly cut round brilliant stone.

  2. Try the ‘Fog Test’ (or ‘Breath Test’):

    Since diamonds are efficient heat conductors, once you breathe on a real diamond the fog should disperse immediately. If the stone is a fake diamond the top will stay foggy for a few seconds longer. This test works best with a clean stone.

  3. Test with a Thermal Conductivity Probe (also known as a diamond tester):

    As mentioned, diamonds are efficient heat conductors. Using the thermal test separates most fake diamonds from real diamonds by detecting the rate the stone disperses heat. This test works on most gemstones, with an exception being synthetic moissanite. A synthetic moissanite stone may register as a real diamond with the thermal test.

  4. Use Magnification:

    If you have access to a jeweler’s loupe or microscope there are many observations you can make to help determine if the stone is a real diamond. If the stone passes the heat test, you will want to confirm that it is a real diamond and not a moissanite. Using magnification, look at the gemstone through one of the bezel or star facets on the crown. If the stone shows doubling, which means it looks like there are two of each facet line, then it is probably a moissanite. If you see only one of each facet line (singly refractive) and it passed the heat test then it may be a natural diamond.

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Danielee, welcome to DiamondReview

Those tests are "popular" but quite unreliable, or depending on factors such as expertise/training of the loupe holder which are not easy to control.

Also, these are copy-pasted from a jeweller's website. Why? Do you have any relationship with them?

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Hi I recently did a diamond test on this ring i have and it tested back as diamond. It is fairly big and heard blue diamonds are extremely rare at that size.  I'm not sure it is diamond or something that the tester would read as being a diamond and would like some feedback. Here are pictures of the ring 






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2 hours ago, Mandystars said:

Hi I recently did a diamond test on this ring i have and it tested back as diamond. It is fairly big and heard blue diamonds are extremely rare at that size.  I'm not sure it is diamond or something that the tester would read as being a diamond and would like some feedback. Here are pictures of the ring 

Hi Mandystars, welcome to Diamond Review!

A diamond of that size would be rare in any case, and natural blue diamonds are extremely rare in any size.Here is a photo of a natural diamond in what seems to be a fairly similar colour, and this little piggy at 0.22 ct costs in excess of $70,000, so you can imagine what something that seems to be well over 2 carats would go for. So far so good.

blue diamond

Diamond testers come in various shapes, sizes and reliabilities... and most of them fall into the "unreliable" category. Not so good.

Any truly reliable diagnostic would require having the stone in person, but from the photos I would say that what you have is not a diamond, and is not of natural colour. If I were to bet, I would bet what you have is a (probably irradiated) blue topaz. Not good at all, but here is why:

1. It seems to have a much lower refractive index than a diamond; you can see through the stone quite clearly and there is no facet-to-facet reflection

2. The facet junctions seem to be "soft" rather than crisp

3. The cutting pattern is very unusual for a diamond, with what seems to be a 10-mains, two-tier pavilion. It's not impossible to cut a diamond that way, but it would be quite hard (and usually reserved for really big stones, as in 20+ ct.) and without any reason.

4. The discoloured zone at the bottom of the stone, with a yellowish-green colouration is quite typical of irradiated stones.

Here is another image, of a deeply coloured round cut (GIA called it violet, but there's enough blue in it!) to give you an idea of what the genuine article looks like

violet diamond

All this said, as I mentioned above the only reliable identification is one made with the stone in hand; pretty much any good jeweller or even better a gemmologist would be able to tell you very quickly and reliably (and most likely for free) if it is a diamond. In the unlikely case that it is, colour origin can only be determined reliably by a good lab (i.e. GIA - accept no substitutes), but there's no point in spending several hundred dollars until you have reliably identified the gem.

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  • 2 weeks later...

Since we're talking about how to tell diamonds from other things without advanced instrumentation, one of the places to look is at the girdle. For technical manufacturing reasons, diamonds don't have a smooth, curved, polished girdle like this stone. They'll either have a series of small polished facets or a much rougher surface. They're also very rarely this thick and they'll often have tiny remains of the original crystal surface because the cutters want to retain weight.  

Related image

Edited by denverappraiser
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