The distinction between the principal elements that may be collected and those that are only used in an authoritative sense is a distinction between "notional" and "substantive" elements.
The notional elements (String, Language, Organization, Event, and Time) represent intangibles that are separate from the mostly generic Concept element. The Concept element contains the remaining abstract concepts, tangibles in the collective sense (like the idea of a heart versus the actual preserved specimen), and specific intangible concepts (like the color red).
The substantive elements (Work, Object, Being, and Place) are things that may be collected, used in the authoritative sense, or collected and used in the authoritative sense. The Hope Diamond, for instance, may be owned by one organization but, for the rest of us, its record would serve as an authority.
Unlike notional elements, substantive elements may have holdings, and very possibly versions. We are currently investigating the difference, for instance, between beings who get different Being records for their real name and their pseudonyms versus treating pseudonyms as "versions" of a Being.