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Rutile and topaz in Precambrian gneiss, Jefferson and Clear Creek Counties, Colorado

Circular 567

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Abstract

Disseminated rutile and major amounts of topaz have been identified in Precambrian topaz-quartz gneiss northwest of Evergreen, Colo. The rutile occurs in quartz-topaz-sillimanite gneiss that forms a stratigraphic unit which is 11 to 100 feet thick and is identified along strike for more than 7,000 feet. Three composite chip samples taken across this unit contain 2.2 to 4.2 percent of rutile, by weight, in grains averaging from 0.1 to 0.3 millimeter in size. The topaz content, by weight, in the same samples ranges from 23 to 67 percent.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Rutile and topaz in Precambrian gneiss, Jefferson and Clear Creek Counties, Colorado
Series title:
Circular
Series number:
567
Edition:
-
Year Published:
1968
Language:
ENGLISH
Publisher:
[U.S. Geological Survey],
Description:
iii, 7 p. :illus., map. ;26 cm.