The Red Aja Stone (commonly referred to as Red Aja, or simply Aja for short) is an item that spawns in Morioh, with a 1/3 chance of spawning every 1 hour, it despawns every 15 minutes. It can also be dropped by Kira, having a 1/3 chance of dropping.
However in Italy, the spawn rate is every 5 minutes with a very low chance of spawning.
(If you can give any more details about the spawn rate for an aja in italy add it in the comments or dm me on discord: ZapThe)
It has a similar appearance to the animated version. Having a silver encasing with other colored jewels around it. It tends to be very small making the chance that you find it even lower.
If used and the user has Hamon, it will grant them Joseph's Hamon. It can also be used to make Aja Mask by talking to Jotaro Kujo [after completing his quests] if you have Vampire Mask and Red Aja in your inventory (if your current ability has the Ultimate sub-spec or is the Ultimate Lifeform, Jotaro will not give you an Aja Mask). Another one of it's uses is to fill the B.I.G METER, though you need two, as one Aja will only fill the bar half-way.
Note: If you get one and it instantly disappears in your inventory, it means you have completed Jotaro Kujo's 2nd quest. (or a Harvest took it lol)