Gold occurs in quartz veins and associated altered country rocks at the Jabal Guyan ancient mine in southern Saudi Arabia. The gold-bearing veins follow northwest-trending fault zones which cut the Precambrian metavolcanic rocks of the area. The veins are brecciated, and gold may have been remobilized during cataclasis. A second generation of unbrecciated, barren quartz cements the earlier quartz and also occurs in north-northeast-trending veins.
Gold values are greater in waste in the mine area than in vein quartz remaining in the ancient workings, and it is believed that considerable gold was extracted from high-grade ore by the ancient miners.
Exploration drilling to determine if veins and alteration zones persist at depth at the Jabal Guyan mine and examination of other ancient mines in the region are recommended.