Discovery Galactic Fizzing Dig from Horizon Group USA. Of course, girls will love this one too, but my boys always had a natural bent for experimentation and discovery. This kit piques a natural love of discovering their inner archaeologist as they unearth 6 real gemstones included in the kit. It is recommended for ages 12+
The Squishy Diary from It's So Me! is recommended for children ages 6+, but I can see tween girls loving it oh so very much as well. The inside has 60 lined sheets of paper to write your most personal thoughts. Stickers and a unicorn pen are also included. It's the squishy soft pink unicorn cover that will really have the gals swooning. My granddaughter is 6 and she would LOVE this. My niece is 12 and she would love it too, equally, if not more!
Both of these ideas are great for gift giving. I am happy to recommend them both to you!