Jeremy - thanks for your response. I ended up buying the ring... the pearl was 15.1mm in an 18K white gold setting with <1ct pave diamonds. The setting was quite large, i.e. large enough to hold a 15.1mm pearl. I ended up getting the ring for $1500 USD - which was definitely a challenge as they genuinely were reluctant to sell it at that price. The color and quality (AAA - although I understand this is a little judgmental!) of the pearl is lovely.
I also bought a loose tahitian pearl - 14mm - graded AAA and a lovely color. This pearl was easier to judge in terms of quality as I could see the whole pearl. It was priced at $3000 USD... but of course it was over-inflated. I got it for $700. It was by far the best pearl in quality and color/lustre for it's size.
So at the end of the day, I ended up walking away with a gorgeous ring AND a loose pearl for $2200 USD. I was quite happy.
p.s. any thoughts on the prices I ended up paying for each item??
Again, much thanks in advance.
Crystalfly