View source for Crystal ball

{{tool
  | color=glass color
  | tile=[[image:crystal ball.png]]
  | name=crystal ball
  | appearance=glass orb
  | cost=60
  | weight=150
  | material=glass
}}
The '''crystal ball''' is a magical [[tool]] that appears in ''[[NetHack]]''. It is made of [[glass]], and appears as a [[glass orb]] when unidentified.

The [[Orb of Fate]] and [[Orb of Detection]] are [[artifact]] crystal balls, as is the [[defunct features|defunct]] [[Palantir of Westernesse]].

==Generation==
A randomly generated crystal ball will have 1-5 charges and has a {{frac|4}} chance of being blessed, a {{frac|2}} chance of being uncursed, and a {{frac|4}} chance of being cursed.{{refsrc|src/mkobj.c|940|version=NetHack 3.6.7}}

[[Elvenking]]s have a {{frac|50}} chance of [[Monster starting inventory|being generated with]] a crystal ball.{{refsrc|src/makemon.c|256|version=NetHack 3.6.7}}

The fourth variant of [[Medusa's Island]] will always generate a crystal ball underwater in the [[kraken]]'s dwelling, placed on the square just outside the door to that section.{{refsrc|dat/medusa.des|371|version=NetHack 3.6.7}}

==Description==
[[Apply]]ing or [[invoking]] a charged crystal ball while not [[blind]] will initiate an [[intelligence]] check - a cursed crystal ball will always fail the check when used. If the result of a d20 is less than or equal to your intelligence, the check succeeds and can then search for a symbol on the current level, consuming a charge.{{reffunc|detect.c|use_crystal_ball}}{{refsrc|src/detect.c|1095|version=NetHack 3.6.7}} If you fail the check:

* No further effect occurs.
* You are [[confused]] for ''d100'' turns.
* You are [[blind]]ed for ''d100'' turns.
* You [[hallucinate]] for ''d100'' turns.
* The ball explodes, destroying it and dealing ''d30'' damage. This is affected by [[half physical damage]], and artifact crystal balls will not break this way.

Applying a crystal ball will always put you into a helpless trance for 1 to 10 turns - a [[ring of free action]] will not prevent this. Applying a crystal ball with no charges will always reveal nothing, but does not risk negative effects.

On a successful check, you can specify any symbol representing a monster, object or trap. If you try to search for anything else, such as [[stairs]] or other dungeon features, you will instead receive a random message hinting at the location of a special level: [[Delphi]], Medusa's lair, the [[Castle]], or [[Wizard's Tower|the Tower of]] [[the Wizard of Yendor]].{{refsrc|src/detect.c|1042|version=NetHack 3.6.7}}{{refsrc|src/detect.c|1087|version=NetHack 3.6.7}}{{refsrc|src/detect.c|1220|version=NetHack 3.6.7}} The message you receive depends on whether you are in the same [[dungeon branch]] as the target level and its [[dungeon level]] relative to yours: ''"You see <foo>, <where>."''{{reffunc|detect.c|level_distance}} The exact message and location ''<where>'' is determined based on the information in the following table:

{| class="prettytable"
|-
! Dlvl difference
! Message (in the same branch)
! Message (not in the same branch)
|-
| greater than 8-10{{reffunc|detect.c|level_distance|comment=The level difference is compared with the random roll (8 + [[rn2]](3)).}}
| "far below/above"
| "far away"
|-
| greater than 1 but no greater than the above number
| "below/above you"
| "away below/above you"
|-
| 1
| "just below/above"
| "in the distance"
|-
| 0
| "near you"
| "in the distance"{{refsrc|detect.c|776|comment=This particular message is possible, for example, when you are in Sokoban and the target level is the Oracle level.}}
|}

Attempting to use a crystal ball while blind will fail with no chance of negative effects, and does not consume a charge. Using a crystal ball while hallucinating still prompts the intelligence check: failure still has the usual consequences, while passing simply prints a message with no other effect.

Reading an uncursed [[scroll of charging]] and selecting a crystal ball will add one charge, up to a maximum of 5, while a blessed scroll will set the crystal ball to 6 charges instead.

{{upcoming|NetHack 3.7.0|You can now search for [[dungeon feature]]s by entering any of {{white|<}} {{white|>}} [[Altar|{{white|_}}]] [[Throne|{{white|\}}]] [[Sink|{{white|#}}]] [[Fountain|{{white|{}}]] - doing so will find all of these features regardless of which one you entered.

The intelligence check when applying a crystal ball now uses a d8 instead of d20 if it is your own [[quest artifact]], or d16 for other blessed crystal balls.

Crystal balls are now generated with 3-7 charges. Uncursed charging adds 1-2 charges up to the maximum of 7. Blessed charging increases the number of charges to 7 and also blesses the ball. Cursed charging removes all charges and curses the ball.

Applying a [[cancelled]] crystal ball now destroys it, regardless of whether or not it is an artifact.}}

==Strategy==
The crystal ball is characterized by its shortcomings as much as its strengths: it is quite heavy, and successful use makes the player helpless for a period of time. Only [[Elf (starting race)|elves]] can raise their intelligence to 20 naturally without aid from a [[helm of brilliance]]; characters of other races without the helm have a non-trivial chance of failure: {{frac|5}} for [[Orc (starting race)|orcs]] and [[Dwarf (starting race)|dwarves]], {{frac|10}} for [[Human (starting race)|humans]] and {{frac|20}} for [[Gnome (starting race)|gnomes]]. When it ''does'' work, it only allows the user to search for a single class of monster or object; most searching items are completely reliable, non-incapacitating, and will reveal ''all'' monsters or objects on a level.

Generally, do not use a crystal ball if you are in a position where you could be attacked in the next 10 turns, have less than 31 HP, or lack a quick cure for impairments - failure can prove deadly, especially for low-level characters. Non-artifact crystal balls can also easily shatter and must be handled with care,  especially if they are in open inventory or within a non-magical [[container]], and all the more so if you are [[punished]].{{refsrc|src/dothrow.c|2054|nethack=3.6.7|name="breaktest"|comment=<code>breaktest</code> function}}

The crystal ball can still be used effectively beyond [[polyfodder]] for a [[magic marker]]: the most relevant of these uses is for finding the [[vibrating square]] or [[portal]] detection. Though reading a [[scroll of gold detection]] while [[confused]] is usually preferable and much lighter in terms of resources, crystal balls may be more ideal for [[conduct]] players (e.g., [[illiterate]] and/or [[pacifist]]) or very cautious players that do not yet know the scroll of gold detection or other means of object detection. In addition to use on the [[Elemental Planes]], it can also be used to detect traps and search for [[vault]]s to clear them out, including seeking out the [[magic portal]] to [[Fort Ludios]].

[[Tourist]]s are in a somewhat unique position to employ a crystal ball once they maximize intelligence - [[The Platinum Yendorian Express Card]] grants almost unlimited access to charging, and crystal balls do not explode from overcharging.

{{upcoming|3.7.0|As the intelligence check for your own quest artifact crystal ball uses a d8, Valkyries and Archeologists can reliably use their quest artifacts to find the vibrating square and/or spot magic portals on the Planes. A blessed crystal ball can also be reliably used with a minimum of 16 intelligence, making them much easier for non-elves to apply.}}

==History==
The crystal ball is introduced in [[NetHack 3.0.0]].

==Origin==
{{wikipedia|Crystal ball}}
The crystal ball is typically associated with the art of scrying (known in this form as "crystal gazing" or "crystallomancy"), with a history of such going back to the writings of Pliny the Elder in the 1st century CE; crystal gazing was a particular popular pastime in the Victorian era as well. The crystal ball served as a medium through which thoughts were focused, with the intent of detecting significant messages or visions for various purposes: personal guidance, prophecy, revelation, inspiration, or even divination and fortune-telling. 

The small chance that Elvenkings will be generated with a crystal ball is based on the [[wikipedia:Palantír|palantír]], a fictional magical artifact from [[J. R. R. Tolkien]]'s Middle-earth novels that appears as an indestructible ball of crystal, and is used for communicating and viewing the past and future. This serves as the inspiration for the [[Palantir of Westernesse]], the quest artifact for the [[Defunct features|defunct elf role]].

The crystal ball in Medusa's domain may be an allusion to [[wikipedia:Graeae|the Graeae]], three daughters of the sea-deities Phorcys and Ceto and sisters to the Gorgons. The Graeae shared a single eye and tooth, and [[Perseus]] stole their shared eye in order to ransom it for information - depending on the telling, this information entailed the whereabouts of either [[Medusa]] herself or the three objects needed to slay her.

==Messages==
{{message|You may look for an object or monster symbol.|You successfully peered into a crystal ball, and may select a symbol to search for.}}
{{message|Too bad you can't see the crystal ball.|You applied a crystal ball while blind.}}
{{message|The vision is unclear.|You applied a crystal ball without any charges, or else successfully peered into one but did not reveal anything.}}
{{message|You see the Wizard of Yendor gazing out at you.|This is a joke message that has a 1% chance of occurring on a successful peer that does not reveal anything; the purpose is explicitly to try and make players nervous.{{refsrc|src/detect.c|1228|version=NetHack 3.6.7}}}}
{{message|All you see is funky <color> haze.|You applied an uncharged crystal ball while hallucinating.}}
{{message|Whoa! Psychedelic colors, <dude/babe>!<br/>You grok some groovy globs of incandescent lava.<br/>The crystal pulses with sinister <color> light!<br/>You see goldfish swimming above fluorescent rocks.<br/>Oh wow... like a kaleidoscope!<br/>You see tiny snowflakes spinning around a miniature farmhouse.<br/>|You "successfully" peered into a charged crystal ball while hallucinating.}}

==Variants==
===SLASH'EM===
In [[SLASH'EM]], crystal balls are notably the only tool not affected by the amnesia-inducing waters of the [[Castle]]'s moat.

Crystal balls can be [[upgraded]] to [[magic marker]]s and vice versa, making it a useful source of markers for [[gnome]]s or characters with a spare [[potion of gain level]]. The crystal ball's low initial charges mean that you will get at most one low-value scroll out of the resulting marker before you [[recharge]] it back to 50 charges, which is still more than useful enough. While in theory, a player could upgrade a magic marker to a crystal ball in order to obtain many more charges than usually possible, the marker will almost always be more useful unless it is too dried out to write any other scrolls.

SLASH'EM's precursors, [[NetHack Plus]] and [[SLASH 6]], introduced additional orbs - the [[orb of charging]], [[orb of destruction]] and [[orb of enchantment]] - that share the same appearance as the crystal ball. These glass orbs had a base price of 750 [[zm]] and weigh 75 [[aum]], making it somewhat easy to tell an actual crystal ball apart from them via weight testing or price identification. These orbs remain in the code of SLASH'EM as [[deferred feature]]s.{{refsrc|apply.c|3570|version=SLASH'EM 0.0.7E7F2}}{{refsrc|objects.c|858|version=SLASH'EM 0.0.7E7F2}}

===NetHack brass===
[[NetHack brass]] adds the glass orbs from NetHack Plus and SLASH 6, but replaces the orb of destruction with the [[orb of maintenance]]. Additionally, the crystal ball now weighs 75 aum like the other glass orbs, meaning that price identification is the most reliable method to informally identify a glass orb.

===dNetHack===
In [[dNetHack]], crystal balls have their weight significantly reduced to 50 aum.

The Palantir of Westernesse is re-introduced and can be obtained from the [[Elvish Racial Quest]] by elven characters in certain roles, and a set of five [[artifact]] [[Crystals (dNetHack)|crystal balls]] appear in the [[Chaos Temple Quest|Temple of Chaos variant]] of the [[Chaos Quest (dNetHack)|Chaos Quest]].

===xNetHack===
In [[xNetHack]], crystal balls start with ''d25'' charges and weigh only 100 aum. Gazing into them no longer paralyzes you, and a blessed or cursed ball counts as +5 or −5 toward the intelligence check - they will never explode unless cursed. Entering an invalid character to search for in a crystal ball will prompt you again rather than wasting the charge. Uncursed charging of a crystal ball will add ''(d5)+5'' charges.

One of [[Itlachiayaque]]'s invocation effects allows the holder to gaze into it for the same effect as a crystal ball of the same beatitude, akin to the Orb of Detection (which it replaces as the Archeologist quest artifact).

===notdNetHack===
In [[notdNetHack]], in addition to dNetHack details, crystal balls can be resized with an [[upgrade kit]].

===EvilHack===
In [[EvilHack]], a crystal ball is one of the few methods available to see the object type of the [[Sokoban]] prizes behind each door and potentially determine their identity.

==Encyclopedia entry==
{{encyclopedia|
	You look into one of these and see _vapours swirling like
	clouds_.  These shortly clear away to show a sort of video
	without sound of something that is going to happen to you
	soon.  It is seldom good news.
	  [ The Tough Guide to Fantasyland, by Diana Wynne Jones ]
}}

==References==
<references/>
{{nethack-367}}
[[Category:Tools]]