Gold Hill is one of those classic collecting areas for Utah rock hounds, and those others pilgrims willing to travel to the far western reaches of that fine state. Of course, the bi-state town (Nevada-Utah) of Wendover is on the route if one is interested in mining recent gold or needing a motel room and an adult beverage.
In the “old days” I had a research area down west of the Deep Creek Mountains to the south of Wendover and my crew always wanted to stop at the casino for a “good meal”. They seemed not to really like my cooking campfire meals down in the desert! So, it was off to the Stateline Hotel and Casino (currently operating as the Wendover Nugget Hotel and Casino), home of Wendover Will. Seems like a entrepreneur by the name of Bill Smith operated a gasoline station in Utah (right east of the state line). Never one to miss an opportunity, when gambling was legalized in Nevada in 1931 Bill added a casino across the state line! During the years that I was stopping in for a refreshment before heading to the desert, the vehicle was parked in Utah, we crossed a white painted line, and voila---we we in a different world with Wendover Will welcoming all.
Leaving the world of bright lights and tinkling slot machines behind we heading south but often could not resist a side trip to the old mining town of Gold Hill, Utah. I previously wrote about the mines and collecting conichalcite, a bright green copper calcium arsenate hydroxide, [CaCu(AsO4)(OH)]---see that blog on December 8, 2011. The information sign at Gold Hill notes that the usual gold, silver, copper and lead were initially mined but when those minerals became depleted, the boom was over and the town became a ghost. During World War I, arsenic was in demand as insect control for creatures devastating the cotton fields of the southern U. S. So, Gold Hill opened up again and mined arsenates.
|COLORLESS AND VITREOUS ADAMITE CRYSTALS ON LIMONITE. SPECIMEN IS 4.3 CM WIDE.|
Another mineral that Gold Hill is “famous for” is adamite, a zinc arsenate hydroxide [Zn2 (AsO4)(OH)]. Adamite is one of those minerals that usually occurs in the oxidized or secondary mineralized zone where zinc is present, and arsenic was in the hydrothermal solution.
|MODIFIED ORTHORHOMBIC AND COLORLESS CRYSTALS OF ADAMITE. INDIVIDUALS ARE .5MM OR LESS IN LENGTH.|
Most of the Gold Hill adamite that I have seen is composed of very tiny crystal druses or ball-like clusters that are either yellow or various shades of green in color. It appears that either iron or copper make some element substitutions. However, pure adamite is colorless, transparent and quite vitreous. In fact, I paid little attention to my specimen of ademite from Gold Hill since I thought it was just “sort of a pretty” rock with numerous tiny quartz crystals. But, much to my amazement, under high power of a binocular microscope those tiny crystals (mostly modified orthorhombic) turned out to be colorless adamite. Some may have hints of very pale green but with my color blindness, it is hard to tell!
|A VUG IN THE SPECIMEN CONTAINING AN UNKNOWN SPRAY OF MINERALS. THE LONGEST INDIVIDUAL ROD IS ABOUT .5 MM.|
|CLOSE-UP PHOTOMICROGRAPH OF UNKNOWN MINERAL. ANY IDEAS?|
|PHOTOMICROGRAPH OF TINY MAMMILLARY STRUCTURES OF GOETHITE OR PERHAPS LIMONITE. ARE THESE PSEUDOMORPHS AFTER SMITHSONITE?|
I just need to revisit Gold Hill and do some dump digging; however, it is a fair trip from the Springs and with the price of diesel….! But wait, all I would need is a couple of lucky pulls on the machine :)