Onyx bolt tips can be created through the Fletching skill. A player must have a Fletching level of 73 and take a cut onyx and use a chisel with it to make 24 Onyx bolt tips. However, this is not recommended, as 24 onyx bolt tips cost 183000 coins, while a cut onyx costs 1252138 coins.
Attaching onyx bolt tips also requires a Fletching level of 73, and for each onyx bolt tip attached to a rune bolt, a player is granted 9.4 Fletching experience.
Onyx bolt tips are dropped by various monsters. TzHaar can drop bolt tips, but it is not recommended to kill them for it due to their poor drop table and "rare" drop rate. Other high leveled monsters should be killed instead as they drop more bolt tips at a much more common rate.