Metamorphics

A quartzose calc-schist with magnetite from the Precambrian of west Texas (color, 378Kb). Quartz is red, calcite is blue, magnetites are black with spots, talc is black. Sample courtesy of S. Grimes

more of the same sample (color, 536Kb)

and still more (color, 410Kb)


A pelitic schist from the Llano Uplift, Central Texas (color, 630Kb) Quartz is red, plagioclase is dark blue, sillimanite is light blue, haven't checked what the green is yet but it may be epoxy. Black areas are biotite and/or garnet.

Another pelitic schist from the Llano Uplift (color, 473Kb) Quartz is red, plagioclase is blue.


Luminescence haloes can also be seen in the quartz (red) around the garnets (black) in this strange garnetiferous rock from the Park Range of Colorado (color, 252Kb). Bright blue grains are microcline feldspar, dark blue grains in the lower right corner are calcite or dolomite. Sample courtesy of J. Rougvie.

A microfracture in a strange garnet-quartz-carbonate-microcline rock from the Park Range of Colorado (color, 264 Kb). Bright blue grains are microcline feldspar, red grains are quartz, black grains are mostly garnet. SEI image of this same area shows fracture in microcline is filled, fracture in quartz is partially-filled. Sample courtesy of J. Rougvie.


A production of:
Robert M. Reed
Department of Geological Sciences

University of Texas at Austin
rmr@uts.cc.utexas.edu