Vulcanian Type Asteroid
Image from John M Dollan
One of the several dynamically stable orbital zones in most solar systems is that which lies quite close to the parent sun. These epistellar regions often contain a planet of some form, but those that do not almost always have a population of a few hundred asteroidal bodies five kilometers or less in diameter. These bodies are largely unchanged since the formation of the solar system, but because of the intense thermal conditions present they tend to be dense and metallic in nature, and many possess quite unique mineral assemblages not seen on other solar system bodies.
As a consequence of their placement, Vulcanians do not present an impact hazard to Gaian worlds, although they do threaten Vesperian Type planets. Indeed, only the inner planets are threatened by these vast rocks, and that typically ranges out to approximately 3.5 AU. In many systems, however, this population may have long since been gravitationally scattered by still forming planets that migrated inward and eventually were consumed by the sun.
Vulcanians are considered to be among the greatest prizes as far as asteroids are concerned, due to their immense mineralogical wealth. They can also be among the most difficult to procure and to move to a processing site because of thermal stressing, and the energy requirements to move such a body out of the local sun's gravity well.