Image: Gold-quartz placer nugget, Lead SD

Description: Gold-quartz placer nugget (1 cm across) from the Black Hills of South Dakota, USA. This is a modern fluvial pebble composed of native gold (Au) and quartz (SiO2). The gold is ultimately derived from auriferous Precambrian basement rocks in the area of Lead, South Dakota. The now-inactive Homestake Mine, America's largest gold mine, is located in Lead (pronounced "Leed"). Gold masses that accumulate in river or stream gravels, or get trapped in fractures in bedrock-floored rivers, are called placer deposits - such gold is called placer gold. Locality: Elk Creek, west of Rt. 385, southeast of the town of Lead, northern Black Hills, western South Dakota, USA.
Title: Gold-quartz placer nugget, Lead SD
Credit: Gold-quartz placer nugget (derived from auriferous Precambrian basement rocks; Elk Creek, west of Rt. 285, southeast of the town of Lead, northern Black Hills, western South Dakota, USA) 1
Author: James St. John
Usage Terms: Creative Commons Attribution 2.0
License: CC BY 2.0
License Link: http://creativecommons.org/licenses/by/2.0
Attribution Required?: Yes