Congenio Ioun Congenio Ioun was a human arcanist and inventor of the ancient empire of Netheril . He was considered the first great arcanist of Netheril , famed for creating the popular magical items known as " ioun stone s " after him , in 397 NY ( −3462 DR ) . Congenio is known to have created at least thirty different types of " ioun stones " . History . Life . Congenio Ioun was born in 364 NY ( −3495 DR ) , in the early Nether Age of Netheril . He became an arcanist . At the time , Netherese priests and wizards alike believed that large objects such as shields and suits of armor were simply too big to be enchanted , and ( mistakenly ) assumed that only small or slender items — pebbles , small stones , pieces of cloth , dagger s , and the like — could be enchanted to bear magic . Congenio worked under this assumption and so he worked exclusively with small , semi - polished stones . In the year 397 NY ( −3462 DR ) , he created what he initially called " Congenio ' s pebbles " , which were later thought to be the first true magical protection devices . This was a previously unheard - of achievement : he was aged only 33 and this was the first magical item he had created , marking him as one of the greatest arcanists of his age . " Congenio ' s pebbles " soon became enormously popular with his fellow arcanists , and were in great demand . Over the next 54 years , the " anhedral " , " echinid " , " hexagonoid " , " spindle " , " pebble " , " star " , and " round " stones were developed and introduced by Congenio or others . In 451 NY ( −3408 DR ) , at the suggestion of a close friend , Congenio renamed his pebbles to the much more catchy " Ioun ' s stones " . Under this name , the " cephaloid " , " cube " , " cylinder " , " decipton " , " dendroid " , " dodecahedron " , " ellipsoid " , " enneid " , " euhedral " , " hectoid " , " helicid " , " heptid " , " monoclinoid " , " nephroid " , " ovoid " , " octahedron " , " orthorhomboid " , " peg " , " pentahedron " , " prism " , " pyramid " , " rectangle " , " septahedron " , " sexahedron " , " tile " , and " tredyhedron " stones were created by Congenio or others and became widespread in Netheril . Congenio himself created over thirty of these , including the " prism " that allowed one to see in the dark and another that granted its holder a temporarily raised level of experience and might . He lived an incredibly long life , almost a thousand years . In 1319 NY ( −2540 DR ) , Congenio finally passed away — it was said to the realms of the gods . Legacy . After his death , a number of other arcanists continued his work . These researchers made breakthroughs in Congenio ' s original design , in that they simply ignored his consistent design and placed their own spells on whatever gem they had , no matter its shape . The stones became generally known as simply " ioun stones " around 1365 NY ( c . −2494 DR ) . By the 14th century , " ioun stones " were much desired , yet few people — even those who had them — knew where they had originated . Congenio Ioun himself had been long - forgotten , but his name lived on in his greatest creation . Only some sages of the arcane such as Prismal the Outrageous knew something of Congenio Ioun ' s story . Congenio Ioun was one of the few spellcasters of the Nether Age of Netheril to draw the respect of his peers , and one of the very few whose name survived from that ancient time . This was despite him not working in spell research , but in the development of the first magic items . Through his creations , his name lived on for millennia . He was viewed as one the first of the great arcanists of Netheril , and as a genius born before his time . Description . Congenio was never seen without a collection of his namesake stones circling his head at all times . Personality . Some considered Congenio a sly individual . Activities . He was among the few Netherese arcanists who did not concern themselves with creating new spells , instead focusing on the creation of magical items , in particular his " ioun stones " . Owing to prevailing opinions , he worked exclusively with small , semi - polished stones . He adopted the self - imposed limitation of enchanting all stones of the same shape with the same spell , making them more consistent for buyers and eliminating confusion . Rumors and legends . It was rumored that Congenio Ioun himself had created a stone that had given him his great longevity ; he lived almost a thousand years . In his own lifetime , some suspected him of being a student of the Terraseer , but he always managed to evade answering the question when put to him .