Following the reorganisation of 1996, the Unitary Authority of Gwynedd was reconstituted from the administrative county of Gwynedd minus the parts now within the Unitary Authorities of Conwy and Isle of Anglesey. As such, it covers most of the traditional counties of Merionethshire and Caernarfonshire.
The administrative county of Gwynedd was itself only formed during 1974 from the amalgamation of the traditional counties of Merionethshire, Caernarfonshire and Anglesey that that date back to the middle ages.
Mineral specimens from locations listed within this section (ie the part of the Unitary Authority of Gwynedd that previously formed the traditional county of Merionethshire may therefore be labeled as coming from Gwynedd or Merionethshire depending upon the time they were collected.
Mineral specimens from locations within the part of the Unitary Authority of Gwynedd that previously formed the traditional county of Caernarfonshire are listed seperately within that section.
