Fracture-6 is a "bandaged" puzzle with three axes of rotation, based on the geometry of the triangular dipyramid. The three axes are located at each four-sided vertex. Every axis is capable of turning in 90 degree increments, but only when all four edges around that axis are pointing in the same direction. If the edges are not properly aligned the axis will be limited to 180 degree turns. This bandaging makes Fracture-6 very difficult to solve.
Fracture-6 comes as a DIY kit of parts, and you will need to supply your own stickers. The templates for the stickers are available in the instructions forum.
I recommend that unless you are familiar with the process of dyeing these parts, you purchase the puzzle in "Black Strong & Flexible". It costs a bit more than the white material, but it's worth it since the finished puzzle will look and work better. Fracture-6 also requires screws and springs to assemble. These can be purchased through a few different online puzzle sellers. The ones I used came from this shop. You'll need three screws and three springs.
Have fun!