# Touchstone

* 

Name

touchstone

Appearance

gray stone

Damage vs. small

1d3

Damage vs. large

1d3

To-hit bonus

+0

Weapon skill

sling

Size

one-handed

Base price

45 zm

Weight

10

Material

mineral

A touchstone is one of four gray stones that appears in NetHack.

Contents

1 Generation
2 Effects
3 Identification
4 Strategy
5 Messages
6 SLASH'EM
7 Encyclopedia entry
8 References

Generation
Archaeologists always start with an uncursed touchstone, and one is always generated in the inventory of a jewelery shop's shopkeeper.[1]

Effects
The touchstone is used to identify gems by applying the touchstone or rubbing a gem on it. A blessed touchstone will immediately identify the gem, as will an uncursed one in the hands of an archeologist or gnome;[2] this includes both worthless glass and other gray stones, and will also auto-identify the touchstone. A non-blessed touchstone will merely distinguish glass from gems; valuable gems will leave streaks of the gem's color, while glass will leave scratch marks. A cursed touchstone has a 1⁄5 chance of shattering gems that are rubbed on it.[3]
Using a touchstone while hallucinating will produce YAFM without identifying the gem.

Identification
Rubbing an iron item on the touchstone will produce a signature "scritch, scritch" noise, which is the most reliable means of identifying the stone. Rubbing any gem on the touchstone will produce the same noise as the result if you are blind. They can also be identified by price, being the only gray stone with a 45 base price.

Strategy
Blessed touchstones allow you to sell fully identified gems for full price and get the full luck bonus for throwing them to unicorns. For uncursed touchstones, if you formally identify glass from watching the messages, you should type-name the glass before discarding it to avoid the need for redundant testing. You may then use a scroll of identify to formally identify the valuable gems if you do not wish to bless your touchstone.
Rubbing a gem or glass on any other gray stone will make colored scratch marks.[4] Therefore, rubbing a gem or glass on an unidentified gray stone can identify a touchstone (colored streaks or scratch marks) from other gray stones (colored scratch marks).
An unidentified touchstone can be used to distinguish metal objects from non-metal objects using the aforementioned signature noise, but this strategy is somewhat obscure and of limited use. Gauntlets of power and kicking boots are the only items in the game that can be distinguished in this way, potentially serving some use in narrowing down the identity of other gloves or boots.
While hallucinating prevents you from actually using a touchstone to identify gems, attempting to do so will produce a specific message that can indirectly identify an unused gray stone as a touchstone.

Messages
You see 

<color> streaks on the stone.
You rubbed a valuable gem on a touchstone.
You make scratch marks on the stone.
You rubbed a piece of worthless glass on a touchstone.
You make <color> scratch marks on the stone.
You rubbed a gem on a non-touchstone gray stone.
Oh wow, man: Fractals!
You tried to use a touchstone while hallucinating.
SLASH'EM
In SLASH'EM, touchstones can only be used on gems.

Encyclopedia entry

"Gold is tried by a touchstone, men by gold."

[ Chilon (c. 560 BC) ] 

References

↑ src/shknam.c in NetHack 3.6.0, line 671

↑ src/apply.c in NetHack 3.6.0, line 2226

↑ src/apply.c in NetHack 3.6.0, line 2196

↑ src/apply.c in NetHack 3.6.0, line 2276

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.6.4. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-364}} tag to the current version's tag or {{noversion}} as appropriate.

</color></color>