Possible to see no inclusions in natural sapphire?

[jruby8179]

Hi everyone, thank you for taking the time to read. I bought some dark royal blue sapphires from an ebay seller with thousands of positive reviews. I've bought a handful of stones from them before also. The listing says they are natural but I received them today and they seem maybe too good to be true. I have a 10x loupe and they are almost perfectly clear. I don't think I see any inclusions whatsoever.
I've bought natural sapphires before, always heated or treated in some way but I could see inclusions here and there and I actually like them. Reminds me that they come from nature.
My question to those who have more knowledge or experience: is it possible that I might not be able to see inclusions in a sapphire at 10x magnification if they were heated or treated? These are very dark blue sapphires but very clear and rich. It's possible they were a good price because very dark sapphires aren't as desirable typically. In this case it is important to me that they are natural. I emailed the seller but no response yet. Just wanted some professional advice or opinions. Thank you

 

[Bron357]

Dark blue sapphires are often of Australian origin.
One way to check for natural is to place the gem in a glass of water with a clear bottom and put the glass over a strong light source. A natural sapphire should show some variations in colour ie bands of lighter / darker.
On eBay a lot of the gems aren’t natural from the ground. Apart from man made sapphires ie grown in a lab, there are glass filled and Beryllium treated sapphires.
If super dark it can be nigh impossible to see the characteristics that indicate natural from the ground vs grown in a lab. Depending on the price, you probably need a lab report to be sure.
But dark blue sapphires aren’t particularly popular so hence their prices are cheaper.

 

[Frost]

Both heated and unheated sapphires can theoretically be, and very rarely actually are, (almost) microscopically clean.
There are other tell-tale signs of natural stones to look for: color bands, while not always clearly present, are usually a good clue. Corundum growth structure, while also not indicative on its own, can also be corroborating evidence.
The problem with both of those is that they don't on their own theoretically rule out advanced (and rarer) synthetics like flux-grown ones. Those usually rule themselves out via other giveaway inclusions, but still.

Apart from that, advanced lab tests are pretty much the only other thing that can tell you for sure. But there are many cases where a lab won't issue a report at all if they can't find at least something highly indicative of natural or synthetic origin inside the stone under either an immersion microscope or a normal one, regardless of what the advanced instruments tell them. Which is just as well, since such contentious stones are really best avoided entirely as they're likely to cause disagreements and issues as they get re-submitted to various labs in search of answers.

As for reports, like Bron mentioned above, it depends on the price - for very dark, eBay blues, it simply depends on how much you paid. In most cases, if you can't reliably tell that they're natural and if they were really cheap, you can safely assume there's a good reason for that.

P.S. There's another case where they may be natural, but heated stones: if they were heated from so-called 'geuda' corundum (milky, yellowish-white sapphire pebbles that produce very nice colors in some cases after heating).
Those sometimes show absolutely nothing at all inside or out, but there's a really simple way to see if they're natural - you put a strong torch to the girdle of the stone. As it lights up, if you see very clear and strong white bands all over the stone (remnants of silk that otherwise remain invisible if not specifically lit up), you can rest assured that they're natural but at the very least heated.