sapphire engagement rings

Are there ways to tell a natural sapphire from a lab created one? Which one is more expensive?

A natural/unheated sapphire is more desirable, but there are people who prefer the look of a heat treated sapphire because they find the color of an enhanced sapphire richer.

Personally, I would never buy a treated or enhanced gem. Just a personal preference, apart from the fact that their resale value is so much lower than a perfectly natural gem.

I think someone with some considerable experience with jewels would be able to tell the difference between treated and untreated gems, from a close distance.
 
Created sapphires are cheaper - I know because I have one. :P

Much as I always thought I'd have a genuine one, when I came to getting engaged genuine ones were out of my budget.

But it worked out very well for me - genuine sapphires can be extremely dark - almost black in some lights. You have to pay top dollar to get a great blue colour.

Whereas my created sapphire is an amazing true-blue colour - people always go "Wow!" when they see it. And of course I got more bang for my buck.

Now do I tell people it's created? No.... I'm still a little bashful about that. People have funny notions about created stones and I would be very upset if anyone looked down on my ring.
 
Synthetics have the same physical and chemical properties as natural, but will typically have telltale inclusions seen under magnifaction. They will price less than natural sapphires of equal color quality and there are different levels of quality you can get with synthetics depending on which process is used. (Chatam being the one of the finest, and flame fusion being at the lower end).
I personally have a natural sapphire in my engagement ring, and I must say the color is quite unlike any synthetic I have ever seen.
I would suggest looking at a few in person and deciding for yourself what appeals to you. My favorite website for gem stalking is palagems.com. I find their pictures are very true to irl, as is not always the case with many colored gemstone websites.