Just curious if any of you experts could give some idea of what this is from the faceting, inclusions, etc? It's claimed to be a natural sri lanka sapphire, but I doubt it.
Why do you doubt it is a sapphire? A heavily treated sapphire is still a natural sapphire, which could be the reason why the pricing is low (if that is the case). Also, the picture could be photoshopped. I don't like to ID stones using only a picture or two because it is only a guess since I am not able to handle the stone or run some basic tests.
There are no "red flags" to indicate it is not a sapphire. There are also no diagnostic details that would confirm it. With ruby and sapphire, unless you pay a pittance and can live with uncertainty, plan on spending an additional $70ish for postage and an AGL Gembrief report. I do not recommend buying corundum gems online unless the seller guarantees in writing they will refund your purchase price AND the lab cert cost if it does not come back as advertised.
A seller who won't take that risk, either doesn't really know what they are selling, or knows it is not what they claim.
I second, what makes you think it isn't what is advertised? But really, there's no way to really know unless it's looked at by someone competent to evaluate it. You can't tell anything from pictures almost 100% of the time. You're either going to have to trust the vendors word, buy it and have it looked at, or find credible evidence against the vendor's word.
I'm thinking it's synthetic because the price is unbelievably low for the carat weight.
I don't mind buying it if it's actually corundum (synthetic or not), but I don't want glass, a doublet, etc. I would be using it as a temporary stone until I find one that is unheated with a reputable cert, which will take months to save for. BE treatment doesn't bother me for a temporary stone.
I found it's listing and I read some of the negative feedback. A few people said their stones quality was not as pictured and another person said a stone they bought was synthetic. They also have some positive feedback it's true. But I would be wary.
There are several Ebay sellers that typically have "sapphires" that look like your photo - the auctions suggest they are natural sapphires but the auction price suggests otherwise i.e. $0.99 starting price. Whether they are natural, treated or synthetic I don't know but the colour and starting price are usually enough red flags for me to avoid them.
You know, I'm always drawn to those amped up photos on ebay, because the color is so saturated! I guess that's the point - to make it really attractive. But they don't look real and of the ebay stones I've bought that look like that in their photo, none have ever looked that way in reality, because they're so photoshopped. Just in case I was wrong, I went and looked at their feedback on toolhaus.org. Unfortunately, there are more negatives or neutrals on there than I would be comfortable with, several of them disappointed over the fact that IRL the color was not the same.
So, as many do, it appears they amp up the color and I suspect its cheap because it doesn't really look like that. If it were that color, and heat treated only, I would think the price would be well over $1,000. On the other hand, it may be Be treated which would account for vivid color. Why don't you ask the vendor if the photo is truly representative of its color, or whether it has any modifiers?