The Crystal bow is a degradable bow made from enchanting a crystal weapon seed. It requires the completion of Roving Elves to wield, as well as 50 Agility and 70 Ranged. If you die in the wilderness with the crystal bow you will lose it. A crystal weapon seed will drop on the ground. The attack range of the crystal bow is 7 spaces, the same as any shortbow.
A crystal bow can be obtained with one of these four methods:
Using 750 harmonic dust to make one at the crystal singing bowl in the Ithell Clan district of Prifddinas (giving 750 Smithing experience).
Buying one from Islwyn in Isafdar forest for 1,000,000 (this amount does not change)
Choosable reward from Roving Elves (only comes with 20% of its maximum charges)
For the first method, the amount of coins needed to create (and repair) is based on the number of times a crystal weapon/armour seed has been made into an item for coins - the cost is shared over all crystal weapons and shields. The first time costs 1,000,000, and each subsequent creation costs 200,000 less until the fifth time (and every time thereafter), which costs 200,000.
The crystal bow will revert to seed after 50,000 charges of combat, but uses two charges per hit except while within Prifddinas, where it uses one charge per hit. A partially degraded bow can be recharged for a fraction of your current creation cost - if it has 90% charges remaining, and the lowest creation price has been achieved, it would cost 20,000 coins to repair.
Attempting to light a fire using the crystal bow results in the message "The bow resists all attempts to light a fire. It seems that the sentient tools of the elves don't approve you burning down forests." The message used to say "You cannot light the fire, because the Crystal Bow has no string." Prior to the release of RuneScape High Detail, the crystal bow indeed had no string.
Attempting to cast Low Level Alchemy or High Level Alchemy on a crystal bow results in the message "You can't do that to elven crystal!" This is due to a glitch that allowed players to alchemise crystal bows on free-to-play worlds for 540,000 coins each. Players could buy crystal seeds, enchant them into bows for 180,000 coins, and alchemise the bows for significant profit. Because of this, Jagex made it impossible to alchemise members' objects on free-to-play worlds, and made it impossible to alchemise crystal equipment at all.
Before the Evolution of Combat, the crystal bow (as well as shield) would lose some of its combat bonuses each time it degraded. Now the stats remain the same at all charge amounts.