I've owned both stones - iolite and tanzanite. I am not a GIA graduate but depending on their quality they can each be dark or light and resemble one another. For that reason, I can't say which stone is which. The 4 larger square shaped stones are a beautiful iris color (bluish purple). The small round stones (10 of them) are paired between the 4 larger ones. They are a light lavender color. The post backs are stamped 14K but I'm not able to photograph that because it's tiny. I used a magnifying glass to see it. They aren't screw-backs; they push on past a groove in the post. My invoice described the earring as a J-Hoop, meaning it's not a full hoop. I'd say it's about 1/3 of a circle hoop.

To my knowledge Tanzanite only comes from Tanzania in Africa, which is why I put that as country of origin in the Item Details. This stone is NOT to be soaked in jewelry solution based on a couple gemologist friends I have. You could rinse them under warm water and dry them with a soft cotton cloth or consult with your jeweler. FYI: The suede presentation box I'm sending them in are not the brand of the earrings. Supposedly they were from QVC.

Many thanks for looking!