Olinghouse gold - small gold mass at upper left (see arrows on photo below) among small quartz crystals in hydrothermal vein.  The original vein consisted of quartz, gold, and calcite.  The calcite was dissolved away by acids during specimen preparation.

This gold-bearing sample is from the Olinghouse Gold Mine in Nevada, USA.  Rocks in the Olinghouse area are mostly late Paleogene and Neogene lava flows.  The lavas have been faulted by Basin & Range extensional tectonics and mineralized by hydrothermal activity peripheral to some large igneous intrusions.

This rock is not technically a gold ore sample.  It is one of many specimen gold samples from Olinghouse Mine that were intentionally saved & prepared solely for mineral collectors.  Specimen gold from Olinghouse consists principally of wire gold and nest gold.  Nest gold consists of loose aggregates of irregularly twisted gold wires.

Stratigraphy: fracture-filling hydrothermal quartz & gold in greenish altered andesite, Pyramid Sequence, Middle Miocene.

Age of gold mineralization: early Late Miocene, 10-11 m.y.

Locality: Green Hill pit, Olinghouse Mine, northwest of Wadsworth, southern Pah Rah Range, southern Washoe County, western Nevada, USA. (~39 39 44 N, ~119 25 07 W)



Greenish-gray altered andesite (flip side of above specimen) - this is the host rock for the quartz-gold hydrothermal vein shown above.



Info. mostly synthesized from:


Kleine (2004) - Specimen gold from the Olinghouse District, Washoe County, Nevada.  Rocks & Minerals 79(1): 44-53.



Home page