Since the scientists or citizens of a GFFA know that kyber crystals existed in the core of stars, its safe to assume that scientists have sent probes to stars to find out about their composition, correct?
Wait. Maybe. This is why it's called "Star" Wars -- all the major weapons, the lightsabers and the Death Stars, are run on stars. But wait. Carl Sagan said we're all star stuff. So then we're all kyber crystals. So wait. Then... we.. are the stars... that war.... Er but yeah, I used to be under the impression in the old EU that kybers were occasionally harvested from "live" stars, depending on the situation (cold easy ones to pick off), or else similar to what Charles said. But I might be basing that on some fanfic. IIRC kybers used to be super popular among the fanfic community... the old EU didn't seem too keen on elaborating upon the topic in comparison to the new EU. Fanficers really really really love crystals for some reason... it's the whole "magic object" theme.
In the old Legend EU, did Kyber crystals even exist? They were all crystals from Illum. Honestly I never heard of Kyber crystals before until I watched Rogue One.
I believe Kyber Crystals existed in the EU, from one of the older stories. Although i believe it was just one crystal, while Lightsaber Crystals were just called... Lightsaber Crystals. Don't quote me on that though.
There was the Kaiburr Crystal, singular, from Splinter. It also appeared in KOTOR2. The standard lightsaber crystals were adegan crystals, and there were tons of other lightsaber crystals in the EU.
Ah, the Kaiburr Crystal, I remember when that was the spelling, before TCW started using kyber for Force-related crystals (I think the first was for some sort of crystal key to a holocron/datacron?). Back in old EU I think just about any good gem could be used as a lightsaber crystal. Luke made his own in a little furnace, Corran used some pirate loot, etc. Adegan crystals were supposed to be some of the best, but by Luke's time not exactly easy to find any left. It'd be funny if nuEU came up with something like the Sun Crusher just to blow up stars for the materials. Actually, since you mention it, I wonder if stars that Starkiller base drains to fire its superlasers can be mined. I forget if they clarified if Starkiller base just literally killed stars then moved to another system, drew energy from distant stars (with its last shot draining the closest star), or if the star recharged later (which I know sounds stupid, but I honestly have no idea what if any rules were ever established with Starkiller). ...the Crystal Star (before it fell into a black hole) probably wouldn't have counted as a kyber crystal would it? No, never mind, I don't know why old EU ideas are just popping up in my mind.
The second and third draft ANH screenplays have "Kiber crystals", which strengthen Force-users who are in possession of them. Ben explains that the Sith hoarded them all when the Empire took over, giving them the power to wipe out the Jedi. In Splinter of the Mind's Eye, which is a novelization of an early ESB concept, Luke and Leia find a "Kaiburr crystal" on Mimban, and it has the same function as the Kiber crystals in the ANH screeplays. In the short story, "Hammertong: The Tale of the "Tonnika Sisters"", it's said that the Death Stars were powered by crystals of some sort. In Tales of the Jedi: Fall of the Sith Empire, Naga Sadow uses crystals of some sort to power the Corsair, a superweapon that makes stars go supernova. Supershadow made fans think that crystals like this would play a role in the prequels. TCW combined the old concept of Kiber/Kaiburr crystals, lightsaber crystals, the Death Star crystals, and the Corsair's crystals to create "Kyber crystals".
Going by Catalyst, there's a base mineral "kyberite" from which kyber crystals grow - you find a vein of kyberite - you may find kyber crystals in that vein. I think Chirrut's "The strongest stars have hearts of kyber" might be metaphorical rather than literal. Wookieepedia doesn't say anything about crystals being present inside stars: http://starwars.wikia.com/wiki/Kyber_crystal
Yep, I saw it as absolutely metaphorical, and concerning the Death Star anyway, rather than any old star. He focuses on Jyn's kyber necklace, and presumably has some inkling through the Force that she's entwined with the Death Star, Galen, and the kyber research. That kybers are found in stars seems to be supposition. The Starkiller wasn't draining kybers from the stars it consumed—and if the theory about it being Ilum pans out, it wouldn't need to.
If only Kyber crystals can power up lightsaber crystals, then it would have to be a renewable and unlimited resource. Otherwise Jedi would run out of lightsabers very quickly. It's not like they can say: Master Yoda is dead, we will now destroy his lightsaber and recycle the crystal. (Please don't. Have some respect Jedi!) Edit: Oh and just realized that by destroying the Death Star and Starkiller base, all of them kyber crystals are destroyed. Unless we are saying Kyber crystals are indestructible and can be salvaged by tractor beams again like at Endor?
Kybers are naturally occurring on worlds like Ilum and Christophsis, so it doesn't seem like they're in limited supply. The Death Star was only powered by eight crystals, which isn't much in comparison. And the First Order has access to a secret kyber supply in the Unknown Regions (presumably Ilum) to upgrade their weapons with, so there are still enough around even in that era. Kybers don't seem indestructible; the Rebels blew one up, and Kylo's crystal is cracked.
They are very hard to destroy - when a lightsaber is exploded in the Younglings arc of TCW, the crystal itself is fine. And in Catalyst, the crystal itself survived the disastrous explosion that blew up the research facility that was working with it.
The third draft ANH screeplay gives us this dialogue: BEN A Jedi’s power is measured by the amount of the Force that is stored within him, and I have little of the Force left in me. LUKE How can you store an energy field within you? BEN When a creature dies, the force it generated remains. The Force is all around us. It can be collected and transmitted through the use of a Kiber crystal. It’s the only way to amplify the power of the Force within you. Sounds to me like "Kiber crystals" might be a way of storing midichlorians.
The Kaiburr crystal in Splinter of the Mind's Eye amplified Force powers, but that hasn't been picked up by the new canon, which is really only using the name kyber and applying it to the old Adegan crystals.
Keep in mind in the old EU they were able to use a lot of different crystals and gems for lightsaber crystals.
