A gold nugget is a naturally occurring piece of native gold. Watercourses often concentrate nuggets and finer gold in placers. Nuggets are recovered by placer mining, but they are also found in residual deposits where the gold-bearing veins or lodes are weathered. Nuggets are also found in the tailings piles of previous mining operations, especially those left by gold mining dredges.

Formation

Nuggets are gold fragments weathered out of an original lode. 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). Other precious metals such as platinum form nuggets in the same way. A later study of native gold from Arizona, US, based on lead isotopes indicates that a significant part of the mass in alluvial gold nuggets in this area formed within the placer environment.

The 'Gold Nugget' mango (or, Golden Nugget) is a named mango cultivar that originated in south Florida.

History

The original tree was grown by Edward F. Mitchell of Miami, Florida. Saigon was thought to possibly be one of the parents of 'Gold Nugget', but a 2005 pedigree analysis indicated that 'Gold Nugget' was likely an offspring of the 'Kent' mango. Mitchell patented the 'Gold Nugget' in February 1990, which was plant patent number 77158.

The fruit was recognized for its flavor and heavy production characteristics. 'Gold Nugget' is now grown on a small, limited commercial scale in Florida, and is sold as a home dooryard tree by nurseries in the state.

'Gold Nugget' trees are planted in the collections of the USDA's germplasm repository in Miami and the Miami-Dade Fruit and Spice Park in Homestead, Florida.

Description

The skin of the fruit turns yellow orange at maturity, sometimes with some pink blush. The flesh is yellow and virtually fiberless, with a mild sweet flavor, and contains a monoembryonic seed. It is usually of oval shape and weighs under a pound. 'Gold Nugget' fruit typically matures from late-July to August in Florida.