Crystal plate mail
|[ crystal plate mail
|crystal plate mail
A set of crystal plate mail is always generated in one of the niches on the middle floor of Vlad's Tower.
Player monster barbarians, priests and valkyries have a 1⁄2 chance of forcing a random body armor with at least 5 base AC instead of dragon scale mail - that armor has a 1⁄8 chance of being crystal plate mail, for an effective chance of 6.25%.
Crystal plate mail is the second-best armor in the game that does not inhibit spellcasting, after dragon scale mail. However, it is seldom used in practice primarily due to its weight: roles who would most benefit from it typically lack the carrying capacity to reliably carry one. Most spellcasters start with low strength, and Wizards and other casters that could raise their strength to a sufficient level where this armor would be worth considering will typically either have: A) a means of obtaining dragon scale mail, or B) a low enough AC that the additional protection is not worth the weight penalty.
Characters with high strength will usually prefer a dwarvish mithril-coat until they obtain dragon scale mail, and even wearing an elven mithril-coat frees up 300 aum of weight in the inventory while providing only two fewer points of base AC. Characters who can't afford to use metallic armor will usually prefer a studded leather armor. Players still willing to try out crystal plate mail will have to be diligent in their inventory management to avoid being burdened too often.
As crystal plate mail is fragile and easily broken unless worn, be careful when handling it - in particular, beware of using force bolts or a wand of striking in a shop selling crystal plate mail, since most early characters will not be able to pay off the shopkeeper if they break any.
Crystal plate mail is introduced in NetHack 1.3d.
In dNetHack, there is now crystal armor for each part of the body - crystal armor doubles enchantment bonuses (adding full enchantment to both AC and DR, rather than half to each) and can be enchanted safely to +7, so a fully enchanted crystal plate mail can provide high defense.
Crystal plate mail still does not inhibit spellcasting, and its weight is also reduced to a more tolerable 170 aum, but does not provide any magic cancellation. A set can still be found in the same place within Vlad the Impaler's dwelling, which is now the Windowless Tower.
For Samurai, crystal plate mail goes by the name "jade o-yoroi".
In xNetHack, while crystal plate mail is not changed directly, armor with glass as its base material can be shatter-proofed through the usual methods of erosion-proofing armor (e.g. reading a scroll of enchant armor while confused). Worn armor is also subject to a 1⁄4 weight reduction, making crystal plate mail slightly more viable.
Dragon scale mail is replaced with dragon-scaled armor in xNetHack, significantly changing which armor is viable or even "optimal" for a given character; crystal plate mail is likely to be overlooked in favor of comparable mail with a lighter material, such as bone or mithril, for use with dragon scales.
In EvilHack, crystal plate mail is changed considerably. Its weight is reduced to 150 aum, and its base material is gemstone instead of glass, making it shatterproof. It is also immune to disintegration and the revamped destroy armor monster spell, which can now erode armor even if the target has magic resistance.
EvilHack applies a spellcasting penalty to all roles for any worn body armor, with crystal plate mail as the sole exception. Dragon scale mail is replaced with dragon-scaled armor in EvilHack as well - crystal plate mail is among the most enticing armor to merge dragon scales into for casting-focused roles.