The gold of Tolosa was a treasure in a lake where the celts offered many of their warprizes.
However, in 105 BC, the proconsul of Cisalpine Gaul, Quintus Servilius Caepio, reported the discovery of the gold at Tolosa to the Senate, and was charged with sending the treasure back to Rome. Over 50,000 15 lb. bars of gold and 10,000 15 lb. bars of silver were found. The gold disappeared en route, with Strabo mentioning that "it was on account of laying hands on them that Caepio ended his life in misfortunes...". It was reported that the gold was stolen by a band of marauders, with many contemporaries and modern historians believing that Caepio himself had hired them.
that makes 750 000 roman pounds of gold *0.328.9= 246 675 kg or ~ 250 tons of gold!
But however, the account of Poseidonius is more plausible: for he says that the treasure that was found in Tolosa amounted to about fifteen thousand talents (part of it in sacred lakes), unwrought, that is, merely gold and silver bullion
not sure how much that is in kg.