Sparks of Eminence are earned by completing the many Records of Eminence. They cap at 99,999. Only 100,000 total Sparks may be spent every week, resetting Sundays at 8:00 a.m. (PDT) / 3:00 p.m. (GMT) / 4:00 p.m. (BST)
They can be exchanged for items and equipment at the following A.M.A.N. NPCs:
One of the benefits of this system is being able to buy armor and NPC it for a considerable amount of gil. Of the choices for this, there are three choices that give around a 10.25 Gil/Sparks ratio. Below is a breakdown, assuming you have max fame in all areas:
Ribauldequin: 24 key presses to obtain one. Can obtain 72 of them for 49,464 Sparks and NPC them for an approximate total of 507,312 (10.256 gil per spark) or gil (Norg).
Koenig Shield: 26 key presses to obtain one. Can obtain 22 of them for 49,082 Sparks and NPC them for an approximate total of 503,118 (10.250 gil per spark) or gil (Norg).
Acheron Shield: 27 key presses to obtain one. Can obtain 18 of them for 49,590 Sparks and NPC them for 505,284 (10.189 gil per spark) (home nation) or 509,904 gil (10.282 gil per spark) (Norg).