A Carat is a Carat...isn't it?

Any person who's bought jewelry and knows what a carat is probably knows how big it is. I've never heard there was a difference between a carat diamond and a carat gem stone, have you? I recently bid on eBay for a pair of garnet earrings that were advertised as 2 carats. Expecting the stones to be a carat each, I was so disappointed when they arrived in the mail. They were beautiful, but the gems were not 2 carats. They were a total weight of 1 carat, which made the stones about a half carat each.





When I complained to the seller they said they were sorry I was disappointed with the size and asked if I was I going by a carat diamond or a carat gem stone. Am I crazy here? They quickly refunded my paypal account, which I didn't ask for by the way.





I wonder how big they think an inch is...