According to tibia wiki and tibia fandom, the item can be accessed by looting boss Thawing Dragon Lord.
An observation note in the Tibia fandom that says the following:" You can receive one from the accessible chest after using a loaded compass (violet) in the Magic Portal near Andrew Lyze."
Loot: Semi-rare: 0-4 Gold Ingots, Ice Cream Cone (Blue-Barian), Ice Cube.
Rare: Bar of Gold.
"The Crowned Tree NPC can give you information on how to access this boss's room."
And you can get it from the market and by buying from other players.
Bar of Gold | TibiaWiki | Fandom
Thawing Dragon Lord - Tibia Wiki
Thawing Dragon Lord | TibiaWiki | Fandom
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