#slickenlines

If you look carefully at this sample, there is a fabric of small grooved lines running down from the top right hand corner of this sample. These are described as slickensides – grooves that are created as rocks are moving and grinding past each other in a fault zone. Fault zones are good places for fluid flow and mineralization since they’re open cracks that run substantial distances through rocks. Whether this gold was deposited during fault motion and the slickenlines represent a pattern in the rock controlling the gold growth, or the fault kept moving after the gold grew and the gold was ground into…this is truly a golden fault. This sample weighs just about half a kilogram and is about 10 centimeters wide. It is available for auction later this month from Bonhams. -JBB Image credit: https://www.bonhams.com/auctions/26082/lot/164/?category=list&length=214&page=1