London Good Delivery refers to a set of standards established by the London Bullion Market Association (LBMA) for the quality and weight of gold and silver bars traded in the London market. These standards ensure that the bars meet specific criteria, including a minimum purity of 99.5% for gold and 99.9% for silver, making them acceptable for trading among market participants. Bars that meet these standards are stamped with a unique mark, indicating their authenticity and compliance. The London Good Delivery system plays a crucial role in maintaining trust and efficiency in the global precious metals market, facilitating transactions and ensuring quality assurance.