muscovite mica from a pegmatite near Coronel Murta, Minas Gerais, Brazil - hand/display specimen The angular nature of these

The angular nature of these grains shows that transport was short

a characteristic of this sandstone

This peat is silty

or one of those plus some number of coins

as revealed by recent infrared fluorescence spectroscopy and is not graphite-rich dolomitic limestone as formerly thought

muscovite mica from a pegmatite near Coronel Murta, Minas Gerais, Brazil - hand/display specimen The angular nature of thesemuscovite mica KAL3Si3O10(OH)2 Coronel Murta, Minas Gerais, Brazil Muscovite is a common rock forming mineral. In pegmatites, which are essentially giant crystal granitic rocks, muscovite forms large books and can be cleaved into large sheets. It is mined commercially for use as an insulator in transformers and electrical equipment. Scrap muscovite, small flakes, is used as a filler or extender in paints. Transparent in thin sheets, muscovite is