I love to buy gem stones in Turkey. I do not find it strange at all. Turkey is well known for the jewelry it produces.
I really like alexandrite and amethysts. I purchased a huge African amethyst in 2007. I paid I think $200 or maybe $250. Five weeks later a jeweler in the French Quarter in New Orleans offered me $1800. After he appraised it he wanted to buy it.
We have purchased gem stone already set in rings and pendants as well as loose stones. We have some really lovely Zultanite that makes our local jeweler jealous every time he sees it. We bought those stone loose and had them set back in the US, simply because it was a last minute decision and there was no time to get them set in Turkey. In March my husband replaced a white sapphire in a ring he purchased in Turkey in 1965 with a gorgeous emerald.
Jewelry is one thing we always buy in Istanbul. Almost every important piece of jewelry I own has come from there, and every single piece of it has been valued at least as much as three times what I paid for it.
I have several pieces that I purchased in the 1960's and they are just as beautiful as they were then, but worth much more of course. My husband buys gold rings in Turkey, and has always been delighted with his purchases.
If you want gem stones, Istanbul is the place to go. I have absolutely no hesitation purchasing gem stones in Istanbul.