DescriptionTourmaline-mica schist (Precambrian; near Custer, South Dakota, USA) 1 - 53317739513.jpg English: Tourmaline-mica schist from the Precambrian of South...
DescriptionTourmaline-mica schist (Precambrian; near Custer, South Dakota, USA) 3 - 53317855199.jpg English: Tourmaline-mica schist from the Precambrian of South...
DescriptionTourmaline-mica schist (Precambrian; near Custer, South Dakota, USA) 2 - 53317968995.jpg English: Tourmaline-mica schist from the Precambrian of South...
DescriptionTourmaline-mica schist (Precambrian; near Custer, South Dakota, USA) (49155675956).jpg Tourmaline schist from the Precambrian of South Dakota...
DescriptionTourmaline-mica schist (near Custer, South Dakota, USA) (40158163570).jpg Tourmaline-mica schist from the Precambrian of South Dakota, USA...
2,000 feet deep. The Precambrian rocks are a folded and sheared layered sequence of highgrade metasedimentary quartzite, schist, hornblende gneiss, and...
Quartz-mica schist with sillimanite 379 3— Photomicrograph of quartz-mica schist with sillimanite. 381 4—Photomicrograph of quartz-mica schist with garnet...
that of an exceedingly fine-grained mica-schist, the dark or almost black shade being due to the abundance of mica. They are very irregular in shape, and...
Types The barite is a vein deposit in Precambrian rocks. The vermiculite is in altered Precambrian biotite schist or associated pegmatites. The clay is...
the Palaeozoic there are and a third schist, of local which underlies the quartzite, limestone. PRECAMBRIAN. Fordham The Fordham within which in...
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