The quartz from the Middle Pit at Gold Hill, Tooele County, Utah, comes out of the ground with a thick coating of black dirt. The quartz pockets can reach several feet across with quartz crystals reaching 18cm long. All the pockets are filled with a black powdery "crud" that is believed to be nondescript manganese oxides. The quartz from this location is always milky white and is commonly associated with conichalcite.

Here are two specimens that have not been cleaned. Note: picture one is a Japan-law twin 8 cm across.



Here is the same Japan-law twin as shown above after it was soaked in muriatic acid for 24 hours and then pressure washed.




Here are a couple of other examples of quartz. The picture on the left is showing the quartz just out of the ground. The one on the right is after a 24 hour bath in muriatic acid and a pressure washing.