Oliver was content to listen until Arsu had finished, at which point he circled back (verbally, anyway) to the topic of rocks.
Very important, rocks.
"Gems can be really important, yeah!" he answered, enthusiastically. He fired Akari a bright, canine smile, eyes squinted and jaws briefly parted. "Some of them are just rocks! Shiny, pretty," (and maybe that was his crow heritage speaking) "and you can make things with them or just collect them! Others, though--they have magic in them." He lifted his forelimb to tap his own ring-like gemstone, an onyx that had long since shifted into strange, shimmering streaks of gold and magenta. "Then if they get life-magic pushed into 'em they can make new Gembounds! That's how we made you," he added, cheerful.
With the birds-and-bees out of the way, and oblivious to any other questions this might raise (and to Arsu's brief, tightly controlled glance), he put his forelimb down and carried on.