Gold nugget

Nuggets are recovered by placer mining, but they are also found in residual deposits where the gold-bearing veins or lodes are weathered.

[1] They often show signs of abrasive polishing by stream action, and sometimes still contain inclusions of quartz or other lode matrix material.

A 2007 study on Australian nuggets ruled out speculative theories of supergene formation via in-situ precipitation, cold welding of smaller particles, or bacterial concentration, since crystal structures of all of the nuggets examined proved they were originally formed at high temperature deep underground (i.e., they were of hypogene origin).

Purity can be roughly assessed by the nugget color, the richer and deeper the orange-yellow the higher the gold content.

[8] The Canaã nugget, also known as the Pepita Canaa, was found on September 13, 1983, by miners at the Serra Pelada Mine in the State of Para, Brazil.

[13] The Canaã nugget is displayed at the Banco Central Museum in Brazil along with the second and third largest nuggets remaining in existence, weighing respectively 1,506.2 troy ounces (46.85 kg; 103.28 lb) and 1,393.3 troy ounces (43.34 kg; 95.54 lb), which were also found at the Serra Pelada region.

Historic large specimens include the crystalline "Fricot Nugget", weighing 201 troy ounces (6.3 kg; 13.8 lb) – the largest one found during the California Gold Rush.

[16][17][18] Another find, the Lady Hotham, which weighed 98.5 pounds (44.7 kg), was found by a group of nine miners on September 8, 1854, in Canadian Gully, Ballarat at a depth of 135 feet (41.2 m).

It weighed 1,008 troy ounces (31.4 kg; 69.1 lb) and was found by a group of inexperienced miners who had received a supposedly empty claim.