Taxonomy term


Mineral Resource of the Month: Garnet

Garnet is the general name given to a group of complex silicate minerals, all with isometric crystal structure and similar properties and chemical composition. The most common garnet minerals are classified into three groups: the aluminum-garnet group, the chromium-garnet group and the iron-garnet group.

21 Feb 2019

Mineral Resource of the Month: Boron

Boron does not occur in nature in an elemental state. It is always found in oxidized states as borate salts. Four mineral forms account for the majority of the economically viable borate deposits throughout the world: two sodium borates, tincal and kernite; a calcium borate, colemanite; and a sodium-calcium borate, ulexite. Borate deposits are formed in areas that are tectonically active with arid climates. Large deposits are found in the Mojave Desert of the United States near Boron, Calif., the Tethyan belt in western Asia and the Andean belt of South America. Most borates are extracted in California and Turkey.

30 Jan 2019

"Critical Minerals" list snubs copper, sparks discussion of criticality

In 2017, the United States relied on imports for more than half the needed supply of 50 mineral commodities that are critical in manufacturing. Some of the commodities come from just a few major suppliers — especially China and Canada — or are produced in tiny quantities in just a few places. Others come from conflict zones. Some are produced only as byproducts of processing ores of major metals, such as copper and zinc. Such complex international supply chains are at risk of being disrupted by a variety of problems, from trade wars and market volatility to natural disasters and terrorism.

20 Dec 2018

Comment: National Geological Surveys: The past, present and future

The oldest national geological survey (Britain’s) is 183 years old; the youngest (China’s) is 19. Yet all the surveys share commonalities. A symposium last June in Vancouver, British Columbia, examined where surveys have been and where they’re going.

06 Dec 2018

Mineral Resource of the Month: Phosphate

Phosphate rock refers to unprocessed ore and beneficiated concentrates that contain some form of apatite, a group of calcium phosphate minerals. Apatite in phosphate rock is the primary source for phosphorus in phosphate fertilizers. More than 80 percent of the world’s current production of phosphate rock is mined from sedimentary deposits, which were formed by the deposition of phosphate-rich materials in marine regions. Most of the rest comes from igneous deposits of carbonatites and silica-deficient intrusions. The grade of phosphate rock is classified by the phosphorus pentoxide content.

23 Oct 2018

Down to Earth With: Volcanologist Scott Rowland

When Scott Rowland returned to his home on Oahu after earning a bachelor’s degree in geology at Oregon State University, intent on heading to graduate school, he was torn between studying volcanoes or groundwater. Ultimately, he chose to study Hawaii’s basalt lavas as a graduate student at the University of Hawaii at Manoa.

14 Aug 2018

Mineral Resource of the Month: Tin

The main source of tin is cassiterite (SnO2), a tin oxide mineral; cassiterite has been the primary source of tin throughout history. Most of the world’s identified tin resources occur as placer deposits, a large number of which are located along the Southeast Asian tin belt. The remaining resources occur as hydrothermal hard-rock veins. In the United States, tin deposits are rare; there are no known extensive tin placer deposits and the few hard-rock deposits are currently not economically exploitable.

12 Aug 2018

Mineral Resource of the Month: Chromium

Although chromium is a metal, it does not occur naturally in metallic form. Chromium can be found in many minerals, but the only economically significant chromium-bearing mineral is chromite. Chromite has been mined from four different deposit types: stratiform chromite, podiform chromite, placer chromite, and laterite deposits. Most of the world’s resources, however, are located in stratiform chromite deposits, such as the Bushveld Complex in South Africa. The economic potential of chromite resources depends on the thickness and continuity of the deposit and on the grade of the ore. Many of the major stratiform chromite deposits also contain economic levels of platinum, palladium, rhodium, osmium, iridium and ruthenium.

13 Jun 2018

Mineral Resource of the Month: Sulfur

Sulfur is one of the few elements found in elemental form in nature and has been used in elemental form since ancient times. It forms near volcanic vents and fumaroles, and small quantities of native sulfur form during the weathering of sulfate and sulfide minerals. However, the largest concentrations of sulfur are found associated with sulfide ore mineral deposits and with evaporative minerals in salt domes. As the 16th-most abundant element in Earth’s crust, sulfur is plentiful and can be found around the world.

12 Apr 2018

Mineral Resource of the Month: Titanium

Titanium is the ninth-most abundant element in Earth’s crust and is found in nearly all rocks and sediments, although it is not found as a pure metal in nature. It has a strong affinity for oxygen, typically forming oxide minerals — the most important being ilmenite and rutile. Processing of ilmenite and rutile in shoreline (beach) and fluvial (river and stream) heavy mineral sand deposits — found along many continental margins — provides most of the world’s titanium supply. Most of the remaining supply comes from two large hard rock deposits that contain ilmenite.

05 Feb 2018