When one talks about Artifacts, one needs to include which D&D edition one is talking about.
Since the OP was specifically talking about BG here (and more specifically, BG2), we are talking about 2nd edition D&D.
In 2nd edition D&D, there are no "minor" or "major" Artifacts - that came with 3ed D&D. In 2nd edition, there are only Artifacts -
"Further information: List of major artifacts in Dungeons & Dragons
Artifacts are unique, powerful magic items. Unlike typical magic items, artifacts cannot be created in play and cannot be disenchanted or destroyed by mundane means. Each artifact is intelligent and has specific goals. An artifact's power depends on its current attitude towards its wielder; its more powerful effects may work alterations on its wielder as a side effect.
Examples of artifacts include the Axe of the Dwarvish Lords, the Codex of the Infinite Planes, the Eye and Hand of Vecna, Heward's Mystical Organ, the Rod of Seven Parts, the Mace of Cuthbert, the Wand of Orcus, and the Sword of Kas."
Comments
Since the OP was specifically talking about BG here (and more specifically, BG2), we are talking about 2nd edition D&D.
In 2nd edition D&D, there are no "minor" or "major" Artifacts - that came with 3ed D&D. In 2nd edition, there are only Artifacts -
"Further information: List of major artifacts in Dungeons & Dragons
Artifacts are unique, powerful magic items. Unlike typical magic items, artifacts cannot be created in play and cannot be disenchanted or destroyed by mundane means. Each artifact is intelligent and has specific goals. An artifact's power depends on its current attitude towards its wielder; its more powerful effects may work alterations on its wielder as a side effect.
Examples of artifacts include the Axe of the Dwarvish Lords, the Codex of the Infinite Planes, the Eye and Hand of Vecna, Heward's Mystical Organ, the Rod of Seven Parts, the Mace of Cuthbert, the Wand of Orcus, and the Sword of Kas."
From - http://en.wikipedia.org/wiki/Magic_item_(Dungeons_&_Dragons) and specifically, The Book of Artifacts - http://en.wikipedia.org/wiki/Book_of_Artifacts