This is the Absalate from Project 863, if you want to wear this as necklace the hole at the top is 2mm wide so you should have no trouble finding some string or a small chain to put in there
My printing settings for Cura are as follows:
Layer Height: 0.2
Supports: Yes
Build Plate Adhesion: Raft
Enjoy :D
PS, you might have a hard time printing, because of the constant overhangs, and it will take a while to clean up, but once its done it should look good.
The author hasn't provided the model origin yet.