The Attributes, also known as Aspects, are three special traits given to certain Trainers and Pokémon when they are born that marks them as a Legendary's chosen one. Beings with Attributes are, for unknown reasons, attracted to each other like magnets and will, for the most part, wind up meeting and travelling together. Each Attribute also has special powers that are exclusive to the Attribute. There are three Attributes: Hearts of Gold, Souls of Silver, and Minds of Crystal.
Attributes and Aura
People with Attributes do have a different quality to their Aura than other people, but it takes some training to actually be able to determine the Attribute's type, and it does not necessarily mean that they happen to be Aura-senstives. Orlando Rosa's experiments were in part a way to see how Attributes influenced the Auric abilities of their holders.