Gemstones of the Universe, Ranked is an alien encyclopedia mentioned in Dragon Ball Z: Kakarot that ranks the rarest gemstones found in Universe 7.
Overview[]
A copy of the encyclopedia is owned by the alien couple that Gohan and Krillin encounter during the Sub Story "Tourtists in Trouble". While trying to convince the oblivious couple to leave Planet Namek as they unknowingly arrived during the battle on Planet Namek, the unnamed Alien Female mentions they are searching for a rare gemstone called a Maristone which Krillin and Gohan agree to look for in exchange for the couple leaving once they find it. While providing them more information on the stone, the female alien reveals that according to the book, the Maristone is the 19th rarest in the universe and can be naturally found on Planet Namek.
The unnamed Alien Male reveals their ship's radar detected some Maristone in some nearby mountains where Gohan and Krillin manage to find the Maristone, which according to its Event Item Info is a Mineral found on Planet Namek and that its rarity makes it a highly valued gemstone. After returning to the couple and defeating some Combatants harassing them who the couple mistake for actors portraying villains in a stage show, Gohan gives them the stone which the male alien confirms is a Maristone as it matches the Maristone's picture in their encyclopedia. The couple however decide to cut their stay from two nights to one due to their recent good fortune as they are still oblivious to the planet wide invasion by the Frieza Force, forcing Gohan and Krillin to give up as they need to get to Guru's House.