No kidding- I worked the Alaska retail outlet cruise season once for Kabana (couture Australian opal inlay, very fine), and you wouldn't believe how many different names some of the jewelers had for doublet or triplet or just plain synthetic opals out there... honestly, I don't think even some of the jewelers knew they were being duplicitous.
Whenever you're purchasing fine jewelry, or getting ready to spend big bucks on a piece, be sure to ask very specific questions regarding the names of the gem, origin, and specifically whether it is synthetic or natural, or had any treatments- ethical jewelers absolutely must toe the line on disclosure... remember though that not all jewelers are ethical, and it is imperative to educate yourself about gemstones before spending your hard-earned $$.