Prambanan meteorite is on the Finest (crystal structure) Octahedrite, around 5% nickel...
Also you have
Hexahedrites - low nickel bearing (up to 6%)
Octahedrites - medium nickel bearing (5 to 17%, mostly on the lower end) and classified from fine to coarse (in crystal structure) believe to be caused by the speed of cooling.
Ataxites - high nickel bearing (16% plus) note: they show no internal crystal structure.