system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Why did the Jedi switch to only using Kyber for their lightsaber crystals?

I was researching lightsaber construction in the jedi library and I found passages from the old republic referring to jedi using a multitude of different crystals, including various exotic materials like Krayt dragon pearls. What caused this practice to stop? 

Furthermore, these old records do not refer to the more standard crystals as "Kyber" and it seems they were able to be sourced from locations other than the Ilum mines. It almost seems like at some point, the records change to consolidate all crystals under the banner of "Kyber" and to only source from a handful of mines. Why is this?
gpt
While there may be something to the old legends, they are exactly that; legends.  If the practice was ever in place, it fell out of favor so long ago that written records are spotty at best.

The securing of a kyber crystal is as much a ritual as it is a quest; to find and bond with a crystal and, with it, craft a lightsaber.  As it's younglings undertaking this task, it lends itself to 1) have a steady supply of crystals and 2) a place where they can undertake the quest in relative safety.