Every jeweler salesman says this. If you listen long enough they will tell you they dug the gem from the ground themselves and they have a guy in the back who makes all the jewelery in the world.
Also i never understood why people like platinum.
I'm not a jewelry salesman, but my friend who is a bench jeweler (he does repair work) orders replacement stones through them. Since he has a business Tax ID registered with them he can get both stones and jewelry for much cheaper than the public has access to and no, no jeweler selling you their pieces will get you their stuff as cheap as he/I can get it. I'm not looking to make anything off it, was just looking to help people out if they were interested.
No jeweler sells for cost, any telling you that is lying strait to your face. For those looking to buy something for their future wives, only go to places who are currently members of The American Gem Society. These places has much stricter standards on their prices. Chains like Helzberg and Ben Bridge are members but it's mostly limited to small mom and pop places. It's hard for large chains to maintain the standards that AGS requires so you don't see many of them in it.
To cut though BS of price haggling at a place such as, say Helzberg... they do limited discounting but they don't mark their stuff up like companies who are apart of Sterling's stores do (Kay, Zales, Jared, Goodman, ect) simply to make them back down and their discounting works as such. 5% off $500-$999, 10% off $1000 - $2999 and 15% off for $3,000 and up. At the point of like 6-7k they can call a special department they have to give you an additional couple percent off if the sale hinges on it. This is how their discounting works, they aren't giving it to you for cost, they aren't doing anything crazy no matter how much they may say they are they are just giving you a small percentage.
As far as Platinum, many get it because of allergies. As I said before, it's the most hypoallergenic metal there is and for some people, it's their only option. For everyone else, more often than not, we would try to convince people they didn't want Platinum because in the long run people get unhappy with it. Repairs cost 3x as much as gold (one tip runs you $90 as opposed to $30 and so on and so forth) and over time it looks like crap. You have to polish it often so it doesn't look dull and that wears away at the metal over time where as White Gold is a simple Rhodium dip and it looks brand new again for however long it takes your bodys oils/chemistry to break it down again. They only thing it is going for it is it's not a memory metal meaning when it takes an impact and bends, that stress at the point of it bending in typical metal doesn't exist with platinum. It'll fine and never get weak points due to bends like Gold and other metals will.
Once in awhile you'll get Mr. Money Bags who demands Platinum and whatever, but you see it less and less these days.
If anyone has questions about this sort of thing, I would be happy to help.