WebBut felsite or microfelsite is still the generally accepted designation for that very fine-grained, almost cryptocrystalline substance which forms the ground-mass of so many rhyolites, dacites and porphyries. In the hand specimen it is a dull, lustreless, stony-looking aggregate. Under the microscope even with high powers and the very thinnest ... WebMay 2, 2008 · What is the texture of Felsite? Felsite is a light-colored extrusive igneous rock. It is a fine grained but not glassy rock, and it may or may not have phenocrysts or large mineral grains.

Felsite and Porphyry - Compare Nature

WebFelsite is fine-grained but not glassy, and it may or may not have phenocrysts (large mineral grains). It is high in silica or felsic, typically consisting of the minerals quartz, plagioclase … WebFelsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age 1.2 History 1.2.1 Origin Unknown plants for attracting butterflies

In Depth - The North Roe Neolithic

WebFelsite (also called felstone) is a very fine grained volcanic rock that may or may not contain larger crystals. Felsite is a field term for a light colored rock that typically requires … WebMuch of the Darrough Felsite may have undergone extensive siliciflcation, probably as a postcompaction event. Contact relations of the Darrough Felsite indicate that it is younger than pre-Tertiary rocks of the southern Toiyabe Range and the Ophir pluton, here dated at 53.9 m.y. (K-Ar, biotite). WebFelsite definition, a dense, fine-grained, igneous rock consisting typically of feldspar and quartz, both of which may appear as phenocrysts. See more. plants for autumn/winter containers