Star Ocean: Till the End of Time

You might of sold it.

How do u get all that in the first place

Yea, you must have sold it. It is worth A LOT anyway. The good news is, you can still get the item you want w/o the stone. I did. All you need is a team of Eliza, Mackwell, and Misty Lear. It should take about 20 or 30 tries, but you'll eventually get it.

You must have sold it dude because you cant equip it as an accessory.And just for general knowlegde,ther are alot of other things like this cause theres one success rate thing for all types of things like the smithy hammer for smithery,multi flask for compounding,nc program disk for engineering,keen kitchen knife for cooking,so if you obtain these things dont sell em otherwise its youre loss.

As a tag on to civilization47s answer, you can get multiple "Keen Kitchen Knife"s as you need one to get the Killer Chef. The rest are one-time only items. Gunsandredroses is the best answer, it is possible late in the game, but it will take quite a while so patience is necessary.

you could have sold it because it can't be equipped to an accessory slot, to check if you did look in the other items sections of you menu. But getting the philosophers stone isn't too hard to get, if you havn't been to moonbase yet, wait until you are forced to have peppita in your party, temporarily, then go the area where you can access the workshop and use her, misty lear and mackwell. You could use Eliza too but she has a lower success rate then peppita.