They'd be more secretive of that information, but she can surmise it's likely to do with the heat it emits or retains. There's also a sense the Dracone don't try to fully grasp or explore the technical aspects behind their resources, believing it to be a gift from the dragons.

Lava stones can be polished for decoration or jewelry, but they work with common metals, gems, and other stones to decorate their weapons or accessories similar to the rest of Abraxas. She's welcome to take a lava stone as a souvenir. If she pays one of the craftspeople, they would polish it for her. It would be especially shiny.