Crystal shield

The crystal shield is a powerful shield available after a player completes the Roving Elves quest, and a possible reward from this quest along with the Crystal bow. To wield the crystal shield, a player must have 70 Defence and 50 Agility. It can be considered similar to the barrows rewards due to its substantial power and pricey repair costs. The Crystal shield is especially good against Ranged attacks.

The crystal shield degrades over time. When a player obtains a new crystal shield, it will be a "New crystal shield". However, after 250 hits (not damage), it degrades into a "Crystal shield 9/10", and for every 250 hits thereafter it will degrade another 1/10th, until it reverts into a crystal seed after a total of 2,500 hits. As the crystal shield degrades, its defence bonus drops. However, if the crystal shield is imbued using Nightmare Zone points, then it will retain its original stats as it degrades. Once the crystal shield has reverted to a crystal seed, a player can buy a new crystal shield for the cost of 750,000 coins, or have their crystal seed enchanted into a shield by Ilfeen. While having the seed re-enchanted costs 750,000 coins for the first time, the price lowers each time you get it re-enchanted. The first recharge costs 750k coins, the second 600k coins, the third 450k coins, the fourth 300k coins, and the fifth and every time thereafter costs 150k.

An interesting thing to note is that if you are pickpocketing somebody and happen to fail, the amount they hit you for also counts against your shield's charges. Thus, pickpocketing is an effective way to degrade your crystal shield.

Degrading
The crystal shield degrades over time. However, after 250 hitpoints worth of damage, it degrades into a "Crystal shield 9/10", and for every 250 hitpoints of damage taken thereafter it will degrade another 1/10th, until it reverts into a crystal seed after a total of 2,500 hitpoints of damage taken.

As the shield degrades the negative magic and range attack bonuses remain the same while the positive bonuses decrease as shown below.

However, if your shield is imbued (from the Nightmare Zone), your shield will remain the same stats as a full shield as it degrades.

Recharging
Ilfeen will recharge crystal seeds into crystal bows or crystal shields. She can be found teleporting back and forth between two clearings in Isafdar.

Initially, Ilfeen charges 750,000 coins to re-enchant a crystal seed into a crystal shield. However, the price is decreased by 150,000 coins each time Ilfeen re-enchants a seed for a player, in the following manner, until reaching the minimum recharge cost of 150,000 coins:

The amount that Ilfeen charges is dependent on the number of crystal seeds she has re-enchanted, not the number of crystal shields she has recharged. For example, a player who pays Ilfeen 900,000 coins to re-enchant a crystal seed into a crystal bow will only have to pay her 600,000 coins to recharge a seed into a crystal shield.