The lorebook's section for BLM doesn't mention anything about use of the gem(s).
However my take on it would be that there in the past, since the school was quite popular in Shatotto's time, there'd most likely have been more than just one of these. I mean, other lore for soulstones point to the fact that some of them aren't exactly rare, what makes them rare is the fact that just everyone seems to be able to use them.
What makes a person self-immolate is the fact that they lost control, which is a result of them not knowing enough about the spell they were casting. Soulstones pass down knowledge to those that can use them, and so it would essentially "fix" this problem. It probably would take the quest-blm quite a lot of years of study and chasing tomes, risking being burned at the stake and what not to achieve the same level of knowledge to be able to cast these spells without the risk of self-immolation. IF that is even possible in current time, it's not exactly teeming with current examples.
Since the school has been outlawed/banned and obscured for many many many years, there probably aren't many of the gems/soulstones left, which is probably also why the quest NPC's present the gem of shattoto as a mystery they don't completely understand yet. I'd say that it's probable that -the- gem of shattoto is the "strongest" in the bunch since they were the first one to successfully use black magic. That'd be my take on it anyways.
However my take on it would be that there in the past, since the school was quite popular in Shatotto's time, there'd most likely have been more than just one of these. I mean, other lore for soulstones point to the fact that some of them aren't exactly rare, what makes them rare is the fact that just everyone seems to be able to use them.
What makes a person self-immolate is the fact that they lost control, which is a result of them not knowing enough about the spell they were casting. Soulstones pass down knowledge to those that can use them, and so it would essentially "fix" this problem. It probably would take the quest-blm quite a lot of years of study and chasing tomes, risking being burned at the stake and what not to achieve the same level of knowledge to be able to cast these spells without the risk of self-immolation. IF that is even possible in current time, it's not exactly teeming with current examples.
Since the school has been outlawed/banned and obscured for many many many years, there probably aren't many of the gems/soulstones left, which is probably also why the quest NPC's present the gem of shattoto as a mystery they don't completely understand yet. I'd say that it's probable that -the- gem of shattoto is the "strongest" in the bunch since they were the first one to successfully use black magic. That'd be my take on it anyways.
Quote:Soul Crystal blurp:
"Ever since the height of the Allagan Empire in the Third Astral Era, the practice of using crystals to store and impart knowledge has been prevalent in Eorzea. An adornment known as a "soul crystal" us worn close to the skin, where the uncommonly clear facets of the carefully cut shard catch and transcribe the ebb and flow of a soul's aetherical composition- effectively capturing an imperfect echo of the wearer's memories. This arcane tool engraved with the myriad deeds of heroes from eras past was employed by many of the disciplines of yesteryear to preserve and pass on the skills of successive generations of masters.
The wisdom contained in a soul crystal, however, is not so easily drawn forth- an untrained neophyte can not simply pick one up one of these gems and expect his mind to be flooded with the knowledge of advanced spellcraft or combat techniques. Without first attaining sufficient proficiency and tempering one's soul to mirror the maturity of the crystal's contributors, a prospective student will be denied even the slightest glimpse of enlightenment. Thus, as is the case with the more contemporary disciplines, the key to mastering the secrets of a soul crystal lies in diligent study and training."
