Gem
| Item classes | ||
|---|---|---|
| " Amulets | [ Armor | |
| % Comestibles | $ Coins | |
| * Gems | ! Potions | |
| = Rings | ? Scrolls | |
| + Spellbooks | ` Statues | |
| ( Tools | ` Boulders | |
| ) Weapons | / Wands | |
- For the material, see gemstone.
In NetHack, gems are simple and typically lightweight items found in the dungeon. They come in three varieties: valuable gems, worthless pieces of glass which look similar, and gray stones. Another type of item that uses the same glyph is the rock, which is handled differently.
Valuable identified gems may be sold for relatively large amounts of money at most general stores, which makes them valuable as a compact form of money. However, shopkeepers will always buy unidentified gems as if they are worthless glass, and will always sell unidentified gems as if they are valuable, possibly subject to a further 33% surcharge for being unidentified. Valuable gems may also be thrown to a co-aligned unicorn to get a large Luck increase. Throwing any valuable or worthless gem to a unicorn will pacify them, and will variably raise or lower luck in certain cases. See the unicorn page for details. Valuable gems also give score, but as score does not normally matter, this is typically of low importance.
Glass and rocks are relatively worthless, though they can be used for throwing if you should wish to conserve your other attacks. Additionally, they can occasionally be polymorphed into more valuable gems if included in a polypile, though it's not worth wasting a wand charge on them. Rocks can also be changed in to meatballs, useful for taming and for sale in shops.
Despite the name, a worthless piece of <color> glass will not shatter like other glass items if thrown against a wall or dropped while levitating. You can fire them from slings as a lighter version of rocks; like rocks, they can be multishot. If they are used as ammo however, both worthless pieces of glass and precious gems may disappear (like arrows).
Contents
Tables of gems
By value
Some gems' appearances can change. In these cases all the options are listed. The actual appearance is randomly chosen from the options at the beginning of each new game, and is consistent throughout that game (if one fluorite is white, all fluorites in that game will be white). The hardness of a gem can be tested by #engraving with it; if the gem is hard, the game will prompt "What do you want to engrave?"; if it is soft, "What do you want to write in the dust?"
| * | Name | Description | Cost (zm) | Weight | Hardness | Prob (‰) | Material |
|---|---|---|---|---|---|---|---|
*
|
dilithium crystal | white gem | 4500 | 1 | soft | 2 | gemstone |
| *
|
diamond | white gem | 4000 | 1 | HARD | 3 | gemstone |
*
|
ruby | red gem | 3500 | 1 | HARD | 4 | gemstone |
*
|
jacinth stone | orange gem | 3250 | 1 | HARD | 3 | gemstone |
*
|
sapphire | blue gem | 3000 | 1 | HARD | 4 | gemstone |
*
|
black opal | black gem | 2500 | 1 | HARD | 3 | gemstone |
*
|
emerald | green gem | 2500 | 1 | HARD | 5 | gemstone |
| * *
|
turquoise stone | green gem blue gem |
2000 | 1 | soft | 6 | gemstone |
*
|
citrine stone | yellow gem | 1500 | 1 | soft | 4 | gemstone |
| * *
|
aquamarine stone | green gem blue gem |
1500 | 1 | HARD | 6 | gemstone |
*
|
amber stone | yellowish brown gem | 1000 | 1 | soft | 8 | gemstone |
| *
|
topaz stone | yellowish brown gem | 900 | 1 | HARD | 10 | gemstone |
| *
|
jet stone | black gem | 850 | 1 | soft | 6 | gemstone |
| *
|
opal | white gem | 800 | 1 | soft | 12 | gemstone |
| *
|
chrysoberyl stone | yellow gem | 700 | 1 | soft | 8 | gemstone |
| *
|
garnet stone | red gem | 700 | 1 | soft | 12 | gemstone |
*
|
amethyst stone | violet gem | 600 | 1 | soft | 14 | gemstone |
| *
|
jasper stone | red gem | 500 | 1 | soft | 15 | gemstone |
| * * * *
|
fluorite stone | green gem blue gem white gem violet gem |
400 | 1 | soft | 15 | gemstone |
| *
|
jade stone | green gem | 300 | 1 | soft | 10 | gemstone |
| *
|
obsidian stone | black gem | 200 | 1 | soft | 9 | gemstone |
| *
|
agate stone | orange gem | 200 | 1 | soft | 12 | gemstone |
| *
|
worthless piece of white glass | white gem | 0 | 1 | soft | 77 | glass |
| *
|
worthless piece of blue glass | blue gem | 0 | 1 | soft | 77 | glass |
| *
|
worthless piece of red glass | red gem | 0 | 1 | soft | 77 | glass |
| *
|
worthless piece of yellowish brown glass | yellowish brown gem | 0 | 1 | soft | 77 | glass |
| *
|
worthless piece of orange glass | orange gem | 0 | 1 | soft | 76 | glass |
| *
|
worthless piece of yellow glass | yellow gem | 0 | 1 | soft | 77 | glass |
| *
|
worthless piece of black glass | black gem | 0 | 1 | soft | 76 | glass |
| *
|
worthless piece of green glass | green gem | 0 | 1 | soft | 77 | glass |
| *
|
worthless piece of violet glass | violet gem | 0 | 1 | soft | 77 | glass |
*
|
luckstone | gray stone | 60 | 10 | soft | 10 | mineral |
| *
|
loadstone | gray stone | 1 | 500 | soft | 10 | mineral |
| *
|
touchstone | gray stone | 45 | 10 | soft | 8 | mineral |
| *
|
flint stone | gray stone | 1 | 10 | soft | 10 | mineral |
*
|
rock | rock | 0 | 10 | soft | 100 | mineral |
By color
The gems that have a randomized appearance are marked with an asterisk, "*".
A user has suggested improving this page or section as follows:
"The unidentified sell price column hasn't been updated since 3.4.3 and is out of date, and probably nobody cares enough to update it, because the prices are a huge pain to calculate."
| Color | Possibilities | Cost | Unidentified sell price | Level | Hardness | ||
|---|---|---|---|---|---|---|---|
| 0 | 1 | 2 | |||||
| *White
|
dilithium crystal | 4500 | 4 | 4 | 6 | 27 | soft |
| diamond | 4000 | 5 | 5 | 3 | 24 | HARD | |
| opal | 800 | 5 | 7 | 3 | 1 | soft | |
| fluorite stone* | 400 | 4 | 7 | 4 | 1 | soft | |
| worthless glass | 0 | 8 | 6 | 4 | 1 | soft | |
| *Blue
|
sapphire | 3000 | 8 | 3 | 6 | 15 | HARD |
| turquoise stone* | 2000 | 5 | 6 | 5 | 6 | soft | |
| aquamarine stone* | 1500 | 7 | 3 | 3 | 1 | HARD | |
| fluorite stone* | 400 | 4 | 7 | 4 | 1 | soft | |
| worthless glass | 0 | 3 | 7 | 5 | 1 | soft | |
| *Red
|
ruby | 3500 | 6 | 6 | 4 | 21 | HARD |
| garnet stone | 700 | 7 | 4 | 5 | 1 | soft | |
| jasper stone | 500 | 3 | 6 | 3 | 1 | soft | |
| worthless glass | 0 | 4 | 3 | 6 | 1 | soft | |
| *Yellowish brown
|
amber stone | 1000 | 8 | 4 | 4 | 1 | soft |
| topaz stone | 900 | 3 | 5 | 5 | 1 | HARD | |
| worthless glass | 0 | 5 | 4 | 3 | 1 | soft | |
| *Orange
|
jacinth stone | 3250 | 7 | 7 | 5 | 18 | HARD |
| agate stone | 200 | 6 | 4 | 6 | 1 | soft | |
| worthless glass | 0 | 6 | 5 | 4 | 1 | soft | |
| *Yellow
|
citrine stone | 1500 | 6 | 7 | 6 | 3 | soft |
| chrysoberyl stone | 700 | 6 | 3 | 4 | 1 | soft | |
| worthless glass | 0 | 7 | 6 | 5 | 1 | soft | |
| *Black
|
black opal | 2500 | 3 | 4 | 3 | 12 | HARD |
| jet stone | 850 | 4 | 6 | 6 | 1 | soft | |
| obsidian stone | 200 | 5 | 3 | 5 | 1 | soft | |
| worthless glass | 0 | 8 | 7 | 6 | 1 | soft | |
| *Green
|
emerald | 2500 | 4 | 5 | 4 | 9 | HARD |
| aquamarine stone* | 1500 | 7 | 3 | 3 | 1 | HARD | |
| jade stone | 300 | 7 | 5 | 3 | 1 | soft | |
| fluorite stone* | 400 | 4 | 7 | 4 | 1 | soft | |
| turquoise stone* | 2000 | 5 | 6 | 5 | 6 | soft | |
| worthless glass | 0 | 3 | 3 | 3 | 1 | soft | |
| *Violet
|
amethyst stone | 600 | 8 | 5 | 6 | 1 | soft |
| fluorite stone* | 400 | 4 | 7 | 4 | 1 | soft | |
| worthless glass | 0 | 4 | 4 | 4 | 1 | soft | |
Generation and identification
To be formally identified means that a gem can be sold at a shop using its base price instead of just a few zorkmids; even if you've found all the other members of the white gem family, including the worthless glass bauble, the shopkeeper will not take "a white gem called diamond" at face value. Much like other forms of identification, gems can be formally identified by:
- scrolls or spells of identification, the former of which is generally considered wasteful to use on gems unless it is blessed to begin with
- Sitting on thrones and hoping for a blessed identification
- Using a touchstone, which must be blessed to perform formal identification for everyone except gnomes and archeologists (who only require it to be uncursed).
Before all that, there are easy ways of determining which gems are worth the effort of formally identifying.
Some valuable gems can only be generated at specific dungeon levels or below. If a particular valuable gem would have been created but the dungeon level is not deep enough, a different valuable gem will be generated instead. Dungeon level does not otherwise affect gem probability, and the ratio of randomly generated gems to randomly generated glass is roughly 1:4 regardless of dungeon level.
These are the minimum levels for certain valuable gems:
| Dungeon level | Gem |
|---|---|
| 3 | citrine stone |
| 6 | turquoise stone |
| 9 | emerald |
| 12 | black opal |
| 15 | sapphire |
| 18 | jacinth stone |
| 21 | ruby |
| 24 | diamond |
| 27 | dilithium crystal |
Any other gems not listed above can be generated on any dungeon level.
Additionally, there are places where certain types of gems are guaranteed to be generated. Twelve gems – three diamonds (white), three emeralds (green), three rubies (red), and three amethysts (violet) – are guaranteed in the corner turrets of Fort Ludios, for example. Also, each bottom of the Gnomish Mines has several guaranteed gems, including at least an uncursed luckstone and an amethyst.
Amethysts have the special property of converting booze into fruit juice, which may be used to informally identify them (and also booze and fruit juice).
An uncursed touchstone can easily separate glass from valuable gems. Even without one, there are ways of distinguishing valuable gems from glass. Some players type-name all gems to take advantage of the fact the hardness/color/price/is-glass quadruple is unique for each type of gem. The inventory list automatically creates stacks of different unidentified gems that are described as the same color; there is only one pile of worthless glass of any given color. Next is hardness – all hard gems are valuable – and hardness can easily be tested by trying to engrave with gems on the dungeon floor. If you engrave in the dust, the gem is soft; if you scratch the floor itself, the gem is hard. Of the remaining groups of soft gems, you can throw one of each stack at a cross-aligned unicorn while utilizing naming tricks to keep track of which gems were found, which gems were to be thrown at the unicorn, and which gems were rejected by the unicorn. Cross-aligned unicorns only accept valuable gems "hesitatingly" and there is no Luck penalty for killing them, if without a Pet, though there may be an unknown Luck adjustment when they catch said valuable gems.
Do not bother to BUC identify your gems (not counting gray stones) at an altar. They are always generated uncursed and their BUC status has no effect. Marking them uncursed at an altar just causes the gems to fail to stack when you pick up more gems of the same type that haven't been formally BUC identified, wasting inventory slots. This can be particularly annoying if you are distinguishing valuable gems without formally identifying them, e.g. by throwing them at unicorns or using an uncursed touchstone, as it will prevent gems you pick up from stacking with named stacks.
Prices when unidentified
When selling gems which have not been formally identified to a shop, you will be offered a price from one of the "Unidentified sell price" columns. The values here will sometimes allow you to identify the gem. The column used is fixed for each shop (but may differ between shops), which may allow more gems to be identified if the column can first be determined.
The price table depends on compile time options. If you compiled NetHack yourself, check it is still valid.
Gray stones
A gray stone can be one of the following items:
- Touchstones may be used to identify glass from gems, and even the variety of gem if it is a blessed touchstone or you are a gnome or archeologist.
- Luckstones will augment your luck rather impressively; if you have a blessed luckstone and no other luck items, your good Luck will not timeout, bad Luck will, and you'll get +3 extra Luck.
- Loadstones are a pun (dating back to early editions of Dungeons and Dragons): at 500 weight units, they weigh 50 times as much as the other gray stones, and they autocurse (and are generated cursed) so they cannot be dropped.
- Flint stones have no particular purpose, but they do slightly better as sling ammo.
Unlike other gems, unidentified gray stones are priced by shopkeepers at their normal values, so price identification is a viable way to identify them.
SLASH'EM
Due to the existence of migohives, identifying four gems is slightly easier in SLASH'EM, because only these gems are generated in migohives: diamonds, rubies, agate stones, and fluorite stones. Hence, if you find a white gem in a migohive and can engrave with it, it's a diamond, and otherwise it's a fluorite stone. Blue, green, or purple gems found in migohives are also fluorite stones. If you find a red gem in a migohive, it's a ruby, and if you find an orange gem, it's an agate stone.
Alchemy with gems
Valuable gems can be dipped into a potion of acid to make new potions. See Alchemy § Gem alchemy for details.
Encyclopedia entries
Gem or rock
The difference between false memories and true ones is the same as for jewels: it is always the false ones that look the most real, the most brilliant.
Agate
Translucent, cryptocrystalline variety of quartz and a subvariety of chalcedony. Agates are identical in chemical structure to jasper, flint, chert, petrified wood, and tiger's-eye, and are often found in association with opal. The colorful, banded rocks are used as a semiprecious gemstone and in the manufacture of grinding equipment. An agate's banding forms as silica from solution is slowly deposited into cavities and veins in older rock.
Amber
"Tree sap," Wu explained, "often flows over insects and traps them. The insects are then perfectly preserved within the fossil. One finds all kinds of insects in amber - including biting insects that have sucked blood from larger animals."
Diamond
The hardest known mineral (with a hardness of 10 on Mohs' scale). It is an allotropic form of pure carbon that has crystallized in the cubic system, usually as octahedra or cubes, under great pressure.
The diamond, _adamas_ or _dyamas_, is a transparent stone, like crystal, but having the colour of polished iron, but it cannot be destroyed by iron, fire or any other means, unless it is placed in the hot blood of a goat; with sharp pieces of diamond other stones are engraved and polished. It is no greater than a small nut. There are six kinds, however Adamant attracts metal; it expels venom; it produces amber (and is efficacious against empty fears and for those resisting spells). It is found in India, in Greece and in Cyprus, where magicians make use of it. It gives you courage; it averts apparitions; it removes anger and quarrels; it heals the mad; it defends you from your enemies. It should be set in gold or silver and worn on the left arm. It is likewise found in Arabia.
Dilithium
The most famous and the first to be named of the imaginary "minerals" of Star Trek is dilithium. ... Because of this mineral's central role in the storyline, a whole mythology surrounds it. It is, however, a naturally occurring substance within the mythology, as there are various episodes that make reference to the mining of dilithium deposits.... This name itself is imaginary and gives no real information on the structure or make-up of this substance other than that this version of the name implies a lithium and iron-bearing aluminosilicate of some sort. That said, the real mineral that most closely matches the descriptive elements of this name is ferroholmquistite which is a dilithium triferrodiallosilicate. If one goes on the premise that nature follows certain general norms, then one could extrapolate that dilithium might have a similar number of silicon atoms in its structure.
Keeping seven (i.e. hepto) ferrous irons and balancing the oxygens would give a theoretical formula of Li2Fe7Al2Si8O27. A mineral with this composition could theoretically exist, although it is doubtful that it would possess the more fantastic properties ascribed to dilithium.
Emerald
'Put off that mask of burning gold
With emerald eyes.'
'O no, my dear, you make so bold
To find if hearts be wild and wise,
And yet not cold.'
'I would but find what's there to find,
Love or deceit.'
'It was the mask engaged your mind,
And after set your heart to beat,
Not what's behind.'
'But lest you are my enemy,
I must enquire.'
'O no, my dear, let all that be;
What matter, so there is but fire
In you, in me?'
Jacinth stone
Sweet in the rough weather
The voice of the turtle-dove-
'Beautiful altogether
Is my Love.
His Hands are open spread for love
And full of jacinth stones-
As the apple-tree among trees of the grove
Is He among the sons.'
Jade
Nothing grew among the ruins of the city. The streets were broken and the walls of the houses had fallen, but there were no weeds flowering in the cracks and it seemed that the city had but recently been brought down by an earthquake. Only one thing still stood intact, towering over the ruins. It was a gigantic statue of white, gray and green jade - the statue of a naked youth with a face of almost feminine beauty that turned sightless eyes toward the north.
"The eyes!" Duke Avan Astran said. "They're gone!"
Obsidian
A volcanic glass, homogeneous in texture and having a low water content, with a vitreous luster and a conchoidal fracture. The color is commonly black, but may be some shade of red or brown, and cut sections sometimes appear to be green. Like other volcanic glasses, obsidian is a lava that has cooled too quickly for the contained minerals to crystallize. In chemical composition it is rich in silica and similar to granite. It is favored by primitive peoples for knives, arrowheads, spearheads, and other weapons and tools.
Ruby and sapphire
_Corundum._ Mineral, aluminum oxide, Al2O3. The clear varieties are used as gems and the opaque as abrasive materials. Corundum occurs in crystals of the hexagonal system and in masses. It is transparent to opaque and has a vitreous to adamantine luster. [...] The chief corundum gems are the ruby (red) and the sapphire (blue).
Topaz stone
Aluminum silicate mineral with either hydroxyl radicals or fluorine, Al2SiO4(F,OH)2, used as a gem. It is commonly colorless or some shade of pale yellow to wine-yellow; [...] The stone is transparent with a vitreous luster. It has perfect cleavage on the basal pinacoid, but it is nevertheless hard and durable. The brilliant cut is commonly used. Topaz crystals, which are of the orthorhombic system, occur in highly acid igneous rocks, e.g., granites and rhyolites, and in metamorphic rocks, e.g., gneisses and schists.
Turquoise stone
TUBAL: There came divers of Antonio's creditors in my company to Venice that swear he cannot choose but break.
SHYLOCK: I am very glad of it; I'll plague him, I'll torture him; I am glad of it.
TUBAL: One of them showed me a ring that he had of your daughter for a monkey.
SHYLOCK: Out upon her! Thou torturest me, Tubal. It was my turquoise; I had it of Leah when I was a bachelor; I would not have given it for a wilderness of monkeys.
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