Following the reorganisation of 1996, the four Unitary Authorities of Blaenau Gwent, Torfaen, Monmouthshire and Newport were formed from the administrative county of Gwent.
Gwent was itself only formed during the 1974 administrative reorganisation and was roughly the area of the traditional county of Monmouthshire, which dates back to the middle ages.
Mineral specimens from locations within this section may therefore be labeled as coming Blaenau Gwent, Gwent or Monmouthshire depending upon the time they were collected.
