pegmatites

Certain special varieties of igneous rocks, known as pegmatites, carry coarsely crystallized mica and feldspar of commercial value, as well as a considerable variety of precious gems and other commercial minerals.

The Economic Aspect of Geology 1915

- Hector Bore (WA), these tenements contain know Uranium mineralization as well as having several geological targets such as pegmatites and a barite occurrence.

Latest News - Yahoo!7 News 2010

While you're there, if you come across any governmental types who are involved with mining or minerals exploitation, can you ask them if they're ready to dig up the thortveitite containing pegmatites?

The second funniest stuff I read today 2008

In pegmatites, the liquid rock (magma) cools so slowly that crystals have time to grow very large.

Lithium 2009

Feldspar is mined from large granite bodies (called plutons by geologists), from pegmatites (formed when the last fluid stages of a crystallizing granite becomes concentrated in small liquid and vapor-rich pockets that allow the growth of extremely large crystals), and from sands composed mostly of feldspar.

Feldspar 2008

The flake mica produced in the U.S. comes from several sources: the metamorphic rock called schist as a by-product of processing feldspar and kaolin resources, from placer deposits, and from pegmatites.

Mica 2008

Beryl forms distinctive hexagonal prisms, and is found in the igneous rock granite and special igneous rocks, derived from granites, known as pegmatites.

Beryllium 2007

The odds are a thousand to one against there being dilithium pegmatites under Rakatan Mons to begin with.

Firestorm L.A Graf 2000

Apatite is especially abundant in some pegmatites.

The Economic Aspect of Geology 1915

The pegmatites thus afford a connecting link between ores of direct igneous sources and ores formed as "igneous after-effects," which are discussed in the next paragraph.

The Economic Aspect of Geology 1915