This pale, dull trillion-cut topaz is the size of a dwarf's thumb knuckle and radiates a thin, sickly yellow pulse of light that is invisible unless in the darkest of rooms. All who lay eyes upon Hastur's Tooth must Save vs. Insanity or be overcome with madness for 1d6 rounds and run away screaming and spouting gibberish. Those who fall under the gem's effects will see horrible visions of cities beyond the rifts of time and space, filled with the spectacle of the Old Gods feasting on the liquified fear of their conquered subjects. These feverish dreams will occur for several nights, perhaps even enough to interrupt spell preparation.
Those who make their save against seeing the tooth must then make a Save vs. Death Ray every 4 rounds they are within the presence of the gem or take 1d12 radiation damage for each failed save. Anyone touching the gem with bare flesh must make this save every 2 rounds.
The gem may be safely handled only by those wearing Gloves of Dwarvenkind.
The gem grants the possessor the ability to Speak to Elder Gods once per month with a 50% chance of success, at the cost of permanently losing two points of INT each time this is attempted (whether successful or not).
The Gall of Blackwood
This black lump of unfinished coal contains an uncut diamond worth 7,500gp. Good luck getting it out, though, as this lump of coal has been cursed by Starblack Blackstaff of Blackwood, the legendary vivimancer supreme.
The skeleton in which the Gall is lodged has all the abilities of a 7th level Vivimancer, and will attack with all the strange and disturbing spells it has available, including summoning spells. The skeleton itself is a quasi-magical construct having no inherent intelligence; it has been imbued with a shard of Blackstaff's own soul which directs its actions from beyond the veils of death. The Gall can only be retrieved by destroying the shard of Blackstaff's soul—which requires at least a +2 silver weapon and a Holy Word spell or scroll.
If the Gall is retrieved and the diamond removed from the coal, the unfinished gem will act as a Lens of Sublime Refraction when held against the right eye, and as a Gem of Seeing if held against the right. Placing the gem in the mouth will allow the PC to polymorph at will into any creature with equal or lesser hit dice. Swallowing the gem when polymorphed will cause the polymorph to be permanent, even if the gem is retrieved via purging or passing.
But remember, the gem is cursed. Each time the gem is used in any of the above manners, the PC permanently loses 2 hit points. Additionally, anyone who claims ownership of the gem becomes the target of a band of bounty hunting trolls bound by Blackstaff for all eternity to seek the re-interment of the gem in a skeleton's skull--preferably the PC's.
The Turquoise Teat
This longish, highly polished turquoise stone was originally part of a small statuette of Curdle, the Petty Goddess of Blind Milkmaids. If the stone is stroked in a manner similar to that of milking a cow, an inky-black, milk-like substance will burst forth from the stone in thick, sticky ropes. This gel-like substance writhes in the air as if alive, twisting and smoking but not bursting into flame. Anyone touching this "milk" will experience 2d6 of burning damage. Any character attempting to drink this fluid before it hits the ground must make a Save vs. Sanity. Failure means the character removes all armor and weapons and runs away screaming gibberish for 1d6 rounds (which might attract nearby monsters).
Should the character make a successful save while attempting to drink this liquid, the black milk will allow the PC to go 1d8 days without rations and also allows them to heal at twice the normal rate during that time period.
Eye Teeth of the Mouthless Tongues
These are two small children's teeth, highly polished and engraved with intricate carvings of The Mouthless One and her minions.
Removing these precious jewels from the skeleton will summon 10d1000 mouthless tongues, which will attempt to retrieve the gems. PCs must make a Save vs. Insanity based on their CON. Failure means the PC is violently, nauseously ill and suffers a –3 penalty to any and all rolls for 1d4 rounds.
Successfully retaining the Eye Teeth of the Mouthless Tongues grants the possessor the ability to speak and understand all languages at will, but only if one tooth is shoved deep into each ear. Additionally, there is a 30% chance that once a year The Mouthless One will send her minions to attempt the gems' retrieval.