Gem
| Item classes | ||
|---|---|---|
| " Amulets | [ Armor | |
| % Comestibles | $ Coins | |
| * Gems | ! Potions | |
| = Rings | ? Scrolls | |
| + Spellbooks | ` Statues | |
| ( Tools | ` Boulders | |
| ) Weapons | / Wands | |
- For the material, see gemstone.
Gems are simple, (usually) lightweight items you find in the dungeon. They come in three varieties: valuable gems, worthless glass which looks similar, and gray stones. Another type of item that uses the same glyph is the rock, which is dealt with 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. (Gems are subject to the random +33% surcharge in recent versions.) Valuable gems may also be thrown to a co-aligned unicorn in order 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 more details.
More commonly, since money and Luck are overabundant later in the game, players save all of the valuable gems they find, stashing them away so that they can be added to the player's score upon the completion of the game. 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
Gray stones are a catchall for four different objects until they are identified.
- Touchstones may be used to identify glass from gems, and even the variety of gem if it is a blessed touchstone.
- Luckstones will augment your luck rather impressively; if you have a blessed luckstone and no other luckitems, 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.
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. 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 | Material |
|---|---|---|---|---|---|---|
*
|
dilithium crystal | white gem | 4500 | 1 | soft | gemstone |
| *
|
diamond | white gem | 4000 | 1 | HARD | gemstone |
*
|
ruby | red gem | 3500 | 1 | HARD | gemstone |
*
|
jacinth stone | orange gem | 3250 | 1 | HARD | gemstone |
*
|
sapphire | blue gem | 3000 | 1 | HARD | gemstone |
*
|
black opal | black gem | 2500 | 1 | HARD | gemstone |
*
|
emerald | green gem | 2500 | 1 | HARD | gemstone |
| **
|
turquoise stone | green gem blue gem |
2000 | 1 | soft | gemstone |
*
|
citrine stone | yellow gem | 1500 | 1 | soft | gemstone |
| **
|
aquamarine stone | green gem blue gem |
1500 | 1 | HARD | gemstone |
*
|
amber stone | yellowish brown gem | 1000 | 1 | soft | gemstone |
| *
|
topaz stone | yellowish brown gem | 900 | 1 | HARD | gemstone |
| *
|
jet stone | black gem | 850 | 1 | soft | gemstone |
| *
|
opal | white gem | 800 | 1 | soft | gemstone |
| *
|
chrysoberyl stone | yellow gem | 700 | 1 | soft | gemstone |
| *
|
garnet stone | red gem | 700 | 1 | soft | gemstone |
*
|
amethyst stone | violet gem | 600 | 1 | soft | gemstone |
| *
|
jasper stone | red gem | 500 | 1 | soft | gemstone |
| ** **
|
fluorite stone | green gem blue gem white gem violet gem |
400 | 1 | soft | gemstone |
| *
|
jade stone | green gem | 300 | 1 | soft | gemstone |
| *
|
obsidian stone | black gem | 200 | 1 | soft | gemstone |
| *
|
agate stone | orange gem | 200 | 1 | soft | gemstone |
| *
|
worthless piece of white glass | white gem | 0 | 1 | soft | glass |
| *
|
worthless piece of blue glass | blue gem | 0 | 1 | soft | glass |
| *
|
worthless piece of red glass | red gem | 0 | 1 | soft | glass |
| *
|
worthless piece of yellowish brown glass | yellowish brown gem | 0 | 1 | soft | glass |
| *
|
worthless piece of orange glass | orange gem | 0 | 1 | soft | glass |
| *
|
worthless piece of yellow glass | yellow gem | 0 | 1 | soft | glass |
| *
|
worthless piece of black glass | black gem | 0 | 1 | soft | glass |
| *
|
worthless piece of green glass | green gem | 0 | 1 | soft | glass |
| *
|
worthless piece of violet glass | violet gem | 0 | 1 | soft | glass |
*
|
luckstone | gray stone | 60 | 10 | soft | mineral |
| *
|
loadstone | gray stone | 1 | 500 | soft | mineral |
| *
|
touchstone | gray stone | 45 | 10 | soft | mineral |
| *
|
flint stone | gray stone | 1 | 10 | soft | mineral |
*
|
rock | rock | 0 | 10 | soft | mineral |
By color
The gems that have a randomized appearance are marked with an asterisk, "*".
| Color | Possibilities | Cost | Unidentified Sell Price | Hardness | ||
|---|---|---|---|---|---|---|
| 0 | 1 | 2 | ||||
| *White
|
dilithium crystal | 4500 | 4 | 4 | 6 | soft |
| diamond | 4000 | 5 | 5 | 3 | HARD | |
| opal | 800 | 5 | 7 | 3 | soft | |
| fluorite stone* | 400 | 4 | 7 | 4 | soft | |
| worthless glass | 0 | 8 | 6 | 4 | soft | |
| *Blue
|
sapphire | 3000 | 8 | 3 | 6 | HARD |
| turquoise stone* | 2000 | 5 | 6 | 5 | soft | |
| aquamarine stone* | 1500 | 7 | 3 | 3 | HARD | |
| fluorite stone* | 400 | 4 | 7 | 4 | soft | |
| worthless glass | 0 | 3 | 7 | 5 | soft | |
| *Red
|
ruby | 3500 | 6 | 6 | 4 | HARD |
| garnet stone | 700 | 7 | 4 | 5 | soft | |
| jasper stone | 500 | 3 | 6 | 3 | soft | |
| worthless glass | 0 | 4 | 3 | 6 | soft | |
| *Yellowish brown
|
amber stone | 1000 | 8 | 4 | 4 | soft |
| topaz stone | 900 | 3 | 5 | 5 | HARD | |
| worthless glass | 0 | 5 | 4 | 3 | soft | |
| *Orange
|
jacinth stone | 3250 | 7 | 7 | 5 | HARD |
| agate stone | 200 | 6 | 4 | 6 | soft | |
| worthless glass | 0 | 6 | 5 | 4 | soft | |
| *Yellow
|
citrine stone | 1500 | 6 | 7 | 6 | soft |
| chrysoberyl stone | 700 | 6 | 3 | 4 | soft | |
| worthless glass | 0 | 7 | 6 | 5 | soft | |
| *Black
|
black opal | 2500 | 3 | 4 | 3 | HARD |
| jet stone | 850 | 4 | 6 | 6 | soft | |
| obsidian stone | 200 | 5 | 3 | 5 | soft | |
| worthless glass | 0 | 8 | 7 | 6 | soft | |
| *Green
|
emerald | 2500 | 4 | 5 | 4 | HARD |
| aquamarine stone* | 1500 | 7 | 3 | 3 | HARD | |
| jade stone | 300 | 7 | 5 | 3 | soft | |
| fluorite stone* | 400 | 4 | 7 | 4 | soft | |
| turquoise stone* | 2000 | 5 | 6 | 5 | soft | |
| worthless glass | 0 | 3 | 3 | 3 | soft | |
| *Violet
|
amethyst stone | 600 | 8 | 5 | 6 | soft |
| fluorite stone* | 400 | 4 | 7 | 4 | soft | |
| worthless glass | 0 | 4 | 4 | 4 | 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 likely not take "A Gem called Diamond" at face value. Much like other forms of identification, gems can be 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, or using a Touchstone, Blessed for everyone except Gnomes and Archaeologists 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.
NetHack generates specific valuable gems at specific dungeon levels, but only at level generation time. This means that the first wave of monsters will never be holding a valuable gem that is worth more than the dungeon level allows, though subsequent ones may, and the contents of the walls are generated only once. Soft gems found in the early game are likely to be glass, and if they are expensive to buy back from shops, they are worthless. (It's only cheating if you then force the game to close without saving and reload to before the sale.) Valuable $2000 gems start at level 7, $2500 at 10, $3000 at 16, pricier even deeper, so one can never expect to find a valuable green gem before dungeon level 7. See this external link for details and spoilers. 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, at least an Uncursed Luckstone and an Amethyst.
Outside of this issue, there are ways of ruling out valuable gems from worthless glass. Some players type-#name all gems to take advantage of this and of the fact the hardness/color/price/isglass quadruple is unique for each type of gem but hovering over the wiki tables on this page may appear in bad form. Possessing an Uncursed Touchstone can easily separate glass from valuable gems but, in lieu of that, you have a variety of tests one can perform. The most prominent distinction is that the inventory automatically creates stacks of different undefined 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.
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.
SLASH'EM
Due to the existence of migohives, identifying four gems is slightly easier in SLASH'EM, due to the fact that only these gems are generated in migohives- the diamond, the ruby, the agate stone, and the fluorite stone. 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.
