Homura's Soul Gem from Puella Magi Madoka Magica
This is a model of Homura's soul gem, symmetrical and with perfectly sharp corners. I tried to print this in strong and flexible plastic (polished) but the walls at the edges are too thin, so you will have to print in frosted ultra detail.
note: I've only tested printing this in frosted ultra detail, so I can't tell you if detail or frosted detail will work.
There is a hollow version of this model that is $2 cheaper in frosted ultra detail. Contact me if you would like to order that version.