Ruby bolts are Adamantite bolts tipped with Ruby bolt tips. Ruby bolts can be created through the Fletching skill. A player must first have a Fletching level of 63 and take a cut Ruby and use a chisel with it to make 12 Ruby bolt tips (giving ~6.3 fletching exp). Attaching Ruby bolt tips also requires a Fletching level of 63 (and gives 63 exp per set of 10). Once the Ruby bolt tips have been attached, the Adamantite bolts become Ruby bolts.
Ruby bolts can be enchanted through the spell Enchant Crossbow Bolt (Ruby) by a player with level 49 Magic. The spell enchants 10 Ruby bolts at a time, and once they are enchanted they become Enchanted ruby bolts and gain a special ability. Enchanted ruby bolts are enchanted with the Blood Forfeit enchantment. This gives the bolts a chance of removing 10% of the attacker's life points to remove 20% of their target's life points, though it does not work if the attacker cannot spare the life points.