Go right ahead if you want to, but you can buy quite substantial amounts of that for close to £20 from lizzie dukes in argos, and that includes it being mounted.
What would I want to buy it for? I have a half carat of real stone in a ring somewhere. This is far too big for normal jewellery and only selected as a sample.
TBH the largest manufacturable synthetic ones in 200 were a couple of carats AFAIK.
metal is right - this isnt a carbon lab diamond
Its a lab created replica. That could just mean cut glass made in a lab. By the looks of it this is cubic zirconia or something forced to crystalize like diamond (instead of in a cubic structure).
But your principle is right, you can buy lab diamonds that are diamonds for much less that are indistinguishable by everyone. The item you linked just isnt one of them.
I just chose the biggest one I could find easily on Ebay. They have a specific page for cubic zerconia where you can pick up a relatively huge one for less than a pound. I have one in a box, same with several other gems. Emerald is one that has been produced synthetically for a long time while garnet is dirt cheap.
^^
as above I read about this a few years ago,
here is the link to the article I read 7 pages long but worth it
Nice link
[edit] That link explains it, everyone has been brainwashed.