Q&A: Looking for a ~1.25-1.5 ct. Princess Cut Diamond in the $12-15k range, Debating between Online and Brick and Mortar Store Purchase

Hello, While I’m skeptical about pretty much everything on the internet advertising itself as free I figured I’d give this a try. I’m looking for an engagement ring for my girlfriend and I live in the DC area. I’ve started looking around at the local stores and would like to get the process moving soon. From what I’ve gleaned from my girlfriend over the years I’m looking for a princess cut diamond in a unique platinum or white gold setting and it must be sparkly haha.

One of the stores I visited pitched a Firemark diamond. How do you feel about the value of these diamonds? Is it really worth the money? The Firemark was a 1.33c F VS2 for 13k. I was hoping to land more towards 10k for the diamond, and depending on how much I spend on the setting maybe even a little cheaper. I’d like to finish in the 12-15k range but do have a little flexibility if it’s something I really like. I kind of feel like while the Firemark is supposed to have more sparkle and appear bigger, it is significantly more than a comparable standard diamond so I’m not sure if it is worth it.

So in summary my questions to you are:

1) How do you feel about Firemark and other “name brand” cuts
2) What sort of price difference should I really expect between James Allen and a brick and mortar store
3) Do you have any James Allen recommendations for Princess cut diamonds in the ~1.25-1.5c range that fits my price range.
4) Any other tips, advice, or suggestions

I’m interested to see what you have to say. Thanks. 

Thanks for your input so far.

I’m still debating a bit on the setting. It’s going to be white gold or platinum. Definitely not halo. Probably something with some detail or pave that makes it a bit unique. I’m also looking into custom settings a bit. I had seen something similar to this that I liked, but it’s still up in the air right now:

http://michaelbjewelry.com/collection/The-Lace-Collection/Crown-Lace-Ring–37 

Thanks for the input. I requested the certificate.

What made you choose these and specifically love the 1.46?

Is it important to get the best cut that I can afford, or do the cut grades for princess diamonds vary too much to be reliable?

Thanks for your continued help.