The final three have been discovered! They are:

Senastone: Willpower regen of 3% every 5 secs for an hour.
Verillium: Increase max int by 2 for an hour.
Slinkamite: 1/5 cahnce of next eq being only half as long. Lasts an hour.

Congrats to the miners who discovered them!

Penned by My hand on the 12th of Sarapin, in the year 689 AF.