Final stellation of the icosahedron

The final stellation of the icosahedron, also known as the echinahedron, is a noble polyhedron that consists of 20 irregular but triangular-symmetric great enneagrams. It is a stellation of the icosahedron.

It appears as the cell of the dual of the pentagonal-prismatic heptacosiicosachoron.

The ratio between the longest and shortest edges is 1:$$\frac{\sqrt{15+5\sqrt5}}{5}$$ ≈ 1:1.02333, making it a near-miss uniform polyhedron.