White goblin mail is made by giving a Whitefish and a regular goblin mail to Aggie in Draynor. Like all goblin mail, it is too small for players to normally wear as armour. White goblin mail is worn by the Saragorgak goblin tribe.
However, during the Land of the Goblins quest the player can turn into a goblin using a Transmogrification potion to access the tribal areas of the Goblin Cave. While wearing white goblin mail the player can enter the Saragorgak goblin tribe's area and pickpocket the Saragorgak priest to obtain the Saragorgak key required to continue the quest.
White goblin mail cannot be traded, and therefore has no value. It can only occupy space in the inventory or bank. However, the brown goblin mailis tradeable.
Hypothetically, it is possible that White goblin mail could be considered Saradomin aligned in the God Wars Dungeon, as the saragorgak were the tribe Bandos sold to Saradomin. This is only speculation, because goblin mail is too small for players to normally wear as armour.