and pseudomorphs of kaolinized feldspar. Fine silt. and clay particles: largely consist of kaolinite. aggregates and plates, and fuzzy clay (halloysite) ...
eeg.geoscienceworld.org/cgi/reprint/10/2/123.pdf

Early known production extends back to the 18th century when it was said the Cherokee Indians mined and sold partially kaolinized feldspar prior to 1744 ...
www.geology.enr.state.nc.us/Mineral resources/feldmod.html

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Note added at 34 mins (2007-07-23 13:13:18 GMT)
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O link para a primeira referência é:

http://eeg.geoscienceworld.org/cgi/content/abstract/10/2/123...

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Note added at 1 hr (2007-07-23 14:01:07 GMT)
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OK...o link para a primeira ref. é um pouco problemático, então:

Two sill-like masses of quartz and kaolinized feldspar constitute the deposit. ... About 80% of the bodies consists of a quartz core; kaolinized feldspar ...
www.minsocam.org/msa/collectors_corner/arc/quartzdep.htm