Frequently Asked Questions
Minerals
The USGS studies geologic processes that concentrate mineral resources in the Earth's crust, and assesses areas of undiscovered mineral resources. We also collect national and international information on mineral commodities.
The primary methods used to extract minerals from the ground are:
Underground mining
Surface (open pit) mining
Placer mining
The location and shape of the deposit, strength of the rock, ore grade, mining costs, and current market price of the commodity are some of the determining factors for selecting which mining method to use.
Higher-grade...
The following USGS products will be helpful in determining the background levels of various elements in soils and other surficial materials:
Geochemical and Mineralogical Data for Soils of the Conterminous United States (2013) Data for samples collected at three intervals (0-5 cm surficial soils, A-Horizon soils, and C-Horizon soils) across the...
Mineral elements provide the color in fireworks:
Barium produces bright greens
Strontium yields deep reds
Copper produces blues
Sodium yields yellow
Other colors can be made by mixing elements:
Strontium and sodium produce brilliant orange
Titanium, zirconium, and magnesium alloys make silvery white
Copper and strontium make lavender
Gold sparks...