Numbers bolded
Ok, I think I got one. Not sure how good it is but....*shrugs*
Kid was doing some research on which gem he would steal for his next heist. Besides the general 'Big Jewel' criteria, he was looking for ones with something mystical or out of the ordinary. The three he found that seemed promising was a diamond brooch, Oracle's Heart; a ruby set into a headpiece called Crimson Rain; and an emerald in the hilt of a sword, Palotiana.
The Oracle'e Heart was discovered in Greece and articles say that it enabled its discoverer, Ulrich Solomon, to see the future. However, was never reported having empowered anyone else in the same way. But there was another story about a diamond with similar powers that was stolen from a rich family in Russia about a century later. The family never reported it to the authorities, so whether they are the same or not is unknown.
Crimson Rain was used in ceremonial gatherings of the tribes in Africa to hold what would today be seances. Stories tell that even warring tribes would gather when called, because any spirits who were called that were not represented by a tribe would curse that tribe. The legend was passed down by spoken word, so no one knows where it first came from. (He just won't tell anyo-*shot*)
The last, Palotiana, is said to heal the wounds of any warrior who wields it. The writings that said of it's power were lost to a fire about five years after they had been discovered. The only thing that survived said that it had been found in a cave. The group who found it said that they'd followed a map made by an unnamed Japanese who had visited England. The cave was labeled 'Ah Be Baba' on the map, but is found in no other books. It is thought to be a play on Ali Baba.
After ten minutes of thought, Kaito smiled and quickly ran off to make a heist notice. Which jewel did he choose and why?
Note: There might be multiple reasons, since this is an original riddle, but I made it with one in particular in mind. Maybe Kaito will go after the others later, but there is one he chose to prioritize. :V
or one, one, three, five, ten, one, one
Also while looking at swords in caves found an interesting story called "THE SULTAN'S SWORD AND THE CAVE OF THE MACHPELAH"
One last note the other two gems fail the not seeing the light of day and thus it is likely they have had moonlight shine on them. The last one being in a cave is unlikely for that to happen unless the cave opening is at the top of a cave and the gem directly below it.