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The biotites in the exterior aureole become more iron- and titanium-rich as they near contact with the Lilesville Granite. In the inner part of the exterior aureole, potassium-rich feldspar begins to appear as it gets closer to the granite. This part of the exterior aureole is a darker gray matrix composed of quartz, feldspar, and biotite.
Granite (/ ˈ ɡ r æ n ɪ t / GRAN-it) is a coarse-grained intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground. It is common in the continental crust of Earth, where it is found in igneous ...
Rhomb porphyry is a volcanic rock with gray-white large porphyritic rhombus-shaped phenocrysts of feldspar (commonly anorthoclase) embedded in a very fine-grained red-brown matrix. The composition of rhomb porphyry places it in the trachyte – latite classification of the QAPF diagram .
Monzogranite – Biotite granite rocks that are considered to be the final fractionation product of magma – A silica-undersaturated granite with <5% normative quartz; Monzonite – Igneous intrusive rock with low quartz and equal plagioclase and alkali feldspar – a plutonic rock with <5% normative quartz
Augen gneiss, from the German: Augen, meaning "eyes", is a gneiss resulting from metamorphism of granite, which contains characteristic elliptic or lenticular shear-bound grains (porphyroclasts), normally feldspar, surrounded by finer grained material. The finer grained material deforms around the more resistant feldspar grains to produce this ...
The granite of the dimension-stone industry along with truly granitic rock also includes gneiss, gabbro, anorthosite and even some sedimentary rocks. Natural stone is used as architectural stone (construction, flooring, cladding, counter tops, curbing, etc.) and as raw block and monument stone for the funerary trade.
Surface of a marble slab from Sinj, Croatia. A variety of igneous, metamorphic, and sedimentary rocks are used as structural and decorative dimension stone. These rock types are more commonly known as granite, limestone, marble, travertine, quartz-based stone (sandstone, quartzite) and slate.
Porphyritic texture in a granite. This is an intrusive porphyritic rock. The white, square feldspar phenocrysts are much larger than crystals in the surrounding matrix; eastern Sierra Nevada, Rock Creek Canyon, California. A porphyritic volcanic sand grain, as seen under the petrographic microscope. The large grain in the middle is of a much ...