Frequently Asked Questions


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.

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mineral fact sheets
For statistical information about mineral commodities, visit the USGS Commodity Statistics and Information website.
Image: Rare Platinum Nugget
White gold was originally developed to imitate platinum, and is usually an alloy containing 25% nickel and zinc. If stamped 18 karat, it would be 75% pure gold.
Image: Russian Crown Jewels from the USGS Library
The fineness of jewelry gold is stated as the number of parts in twenty-four that are gold. Thus, 24 karat gold is pure gold; 12 K would be an alloy that is half gold and half copper or other metals.
Image: Celestite
A mineral is a naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties. A rock is an aggregate of one or more minerals, or a body of undifferentiated mineral matter.
Silver metal specimen with pen for scale
Sterling silver is the standard of quality for articles containing 92.5% silver and 7.5% copper (and/or other alloys).
Close up of Chalcopyrite
Fool's Gold can be one of three minerals. The most common mineral mistaken for gold is pyrite. Chalcopyrite may also appear gold-like, and weathered mica can mimic gold as well.  Compared to actual gold, these minerals will flake, powder or crumble when poked with a metal point, whereas gold will gouge or indent like soft lead.  In addition,...
Image: Supergene Leached Zone at Silver Bell Mine
Of the 1,740,000 metric tons of silver discovered to date, 55% is found in just four countries on earth. All the silver discovered thus far would fit in a cube 55 meters on a side.
Image shows black pans with gold grains
About 244,000 metric tons of gold has been discovered to date (187,000 metric tons historically produced plus current underground reserves of 57,000 metric tons). Most of that gold has come from just three countries: China, Australia, and South Africa. The United States ranked fourth in gold production in 2016. All of the gold discovered thus far...
Of the 1.52 billion metric tons of copper discovered to date, 56% is found in just four countries: the United States, Chile, China, and Peru. All the copper discovered thus far would fit in a cube 550 meters on a side.
Full view of salt, sodium, chlorine sample
To maintain our standard of living, each person in the United States requires over 40,641 pounds of minerals each year: 10,525 lbs. of stone 7,501 lbs. of sand and gravel 656 lbs. of cement 160 lbs. of clays 347 lbs. of salt 192 lbs. of phosphate 523 lbs. of nonmetals 292 lbs. of iron ore 46 lbs. of aluminum 12 lbs. of copper 11 lbs. of lead 5 lbs...
Minerals in mobile devices infographic
At today's level of consumption, the average newborn infant will need a lifetime supply of 800 pounds of lead, 750 pounds of zinc, 1,500 pounds of copper, 3,593 pounds of aluminum, 32,700 pounds of iron, 26,550 pounds of clays, 28,213 pounds of salt, and 1,238,101 pounds of stone, sand, gravel, and cement.
Image: Hydraulic Gold Mining
Minerals must be mined from the ground, either by surface, underground, or drilling methods. Sand and gravel is usually mined in surface pits or rock is crushed to size, gold is mined in surface pits, underground mines, and in streams and rivers.