The Oxford Names Companion, OUP "Scottish Forenames" - Donald Whyte, FGH, FSG
Chambers Dictionary [2003]
Notes:
English and Italian diminutive of Georgina/Giorgina and sometimes Regina; also an Italian diminutive of Luigina. Gina is now becoming a popular given name in many countries.
Thanks to Donald Whyte who provided much of the initial information for this site.