This shape is an interesting variation on the traditional 10 sided die.
This 10 sided die is a lat-long polyisohedron, an order 2 polyisohedron. There are actually 20 triangular sides to this shape, where the sides aren't all equivalent. I've combined adjacent pairs together so that each of the resulting 10 sides can be rolled with equal probability.
For more information on unique dice shapes, see http://loki3.com/poly/fair-dice.html.