Cruor

From FFXI Wiki

The currency of Abyssea. A naturally occurring mineral found in the hordes that have overrun Abyssea, it is useful as a power source and for construction.

Cruor can be gained from completing Abyssean quests, from defeating Abyssean monsters while under visitant status, and from completing Voidwatch battles. it can be spent by speaking with Cruor Prospector NPCs.