Back to IGS | FAQ | Contact

Gem lab certificate about enhanced rubies


Dear All
A am attaching a certificate of a 2.03 carat ruby issued by IGS. In it it states that the ruby is enhanced.Rubies are generally enhanced by thermal processes .Some foreign substances may occur in the fissures due to enhancement process.
How is this certificate to be interpreted.
---- 1) Is it heated only
------2)are the inclusion crystals in the natural corundum converted to other foreign particles, since their melting point is low compared to enhancement temperature
------3)May occur in certificate does not mean they are present.
How can we interpret this certificate in trade


This subject is still a bitter pill for me. In 2012 i bought a ruby from a Florida gem dealer who spit out lies about how good his ruby was, he noted visible silk as a form of proof of untreated ruby. I fell for his lies & later was proved to be the target of a scam. After purchase, i was given papers showing ‘common’ under treatment for ruby which didnt inform the buyer of anything about the stone, I know better now & the state of Florida knows who this company is, I will tell all who ask. This is a buyer beware type of issue, most rubies, about 95% or more are heated & a good part of this treatment includes chemicals & glass fillers that can be seen under a scope if one knows what to look for. Carefully read all papers u get with the stone, before buying if u can, even today, cutters are applying ‘low heat’, @ 500-700 degrees celsius to ruby or sapphire to very slightly clean the interior of the stone, but even this is traceable under a scope. I now have 2 rubies that are untreated, certed by GIA & a treat to see with a intense difference from the treated stones Ive seen-be an intense buyer-stevie…[the top stone is untreated & certed, GIA]


What is the weight of this ruby you kept in picture.can I know price of it.
Thank you in advance


Thanku for ur question, the ruby is Mozambique, 3.02ct, rated at VS clarity, 7x7x5mm, cushion cut, under close exam, u can see the silk/rutile very lightly within the stone, a really neat thing to see. The latest appraisal for insurance on this stone is over $40,000.00/stone. My actual cost is way less than 8% of that figure-stevie…


Thank you for the information and the photograph .You purchased for nearly 35000 USD.


Im thinking u misunderstood my post-my purchase price is less than $5,000.00 USD, I do very intense shopping for decent stones for sale at the right time & price-A one time shot at good stones-good sales to be had-stevie…


That certificate is issued by IGI not IGS. I don’t even think IGI issue certificates it is a qualification and not a lab. You may see a certificate with the geologists qualifications on the bottom showing IGS but not the top.
That said you will be hard pushed to purchase a ruby that has not been enhanced in some way for less than a new car. The very nature of all corundum means most have inclusions or fissures. That said they do exist and if u had a few IF untreated rubies I would be very happy.
Below is a 3.02ct. Ruby in enhanced. If you look carefully you can see a dark inclusion and a is not very clear but to the eye without a look it looks good.


Hi just thought I would share some photo’s of African rubies I have.
bought these in the rough about 25 years ago, they come from the Songea or Tunduru region of East Africa. They have that garnet look about them but they are natural untreated rubies.


I will try and load again. file exceeded limit


Thanks both of you.
Sorry it is IGI not IGS. IGI issues certificates.
I overlooked the decimal point and hence misunderstood the price.


can we see silky inclusions in glass filled rubies also.?
Thanks in advance


When u are talkin ‘glass-filled, serious heated material’ then are lookin for silk/rutile inclusions in ruby/sapphire ur looking at remnants of silk replaced by melted crystals, small cloudy formations around fissures in the stone & new kinds of ‘silk’ formed by heating the ruby, nothing like the natural fine formations in untreated stone. In short, heating the ruby actually melts the silk & that is absorbed back into the stone, if done right, u have a cleaner looking ruby in most cases but there is usually other types of residue from the heat that professionals can pickup under close exam. Untreated rubies are a joy to see under a scope because of actually seeing such fine material & how it is arranged by nature-really neat!-stevie…


Sorry my picture failed to load. Second try from my laptop instead of phone.

I hate mobile phones for this: look what I wrote

“Below is a 3.02ct. Ruby in enhanced. If you look carefully you can see a dark inclusion and a is not very clear but to the eye without a look it looks good”

Should be unenhanced - no treatment.
Eye clear i.e. no loop and it looks good.


Hi Nigel, just looking at your ruby, is the spot black or is it a dark blue/purple, if so it may, probably has been heat treated and beryllium treated you get that dark blue/purple spots in ruby after this treatment.
just an observation


Thanks for the observation. The spot is black and under the microscope in a dark field looks like a tiny piece of rock with sharp crystalline structure. The crystalline structure of the ruby is very fine without evidence of heat although I detected a small vein of wax behind the spot. Possibly to hide a fissure there but is nothing on the crown. However, as I only paid $50 a ct and it tests as ruby. I am not too worried about it’s origin or treatment. It is worth knowing that I collect lame and flawed gemstones no one else wants because they are cheap and infinitely more interesting under a microscope than the boring, perfectly clear top quality ones that hit the headlines and the jewelry stores.
Note that my wife and I are both on the lookout for the unusual, rare and interesting ones. To date we have over 1500 eclectic examples no self respecting jeweler would ever cintemplate for a mount.


Hi Nigel, good to know, I have a large number of quality gems cut and uncut, but also plenty of other not so good quality gems as well, I will hunt around in my back yard and see if I can find anything that may interest you, if I do I will send you photo’s of same



Thanks Syd we are always on the look out for the rare and interesting.
We don’t have any benitite a nice 5ct piece would fit in nicely for 20$… :wink: