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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 ...
Pikes Peak granite is a 1.08 billion year old Late-Precambrian geologic formation found in the central part of the Front Range of Colorado.It is a coarse-grained pink to light red syenogranite with minor gray monzogranite, and it has a distinctive brick-red appearance where it outcrops.
Granite, slate and aggregate are still quarried and china-clay extraction continues on a large scale. There are ample supplies of granite worth the cost of shipping out of the county and much Cornish granite has been used in distant places. It is one of the most appropriate materials for memorials and examples are found in most parts of Cornwall.
It is a favorite collecting area for amateur and serious rock hounds. Scientists from around the world come to Colorado to study the minerals of this region. Because the granite covers a large portion of the Colorado Front Range, there are good mineral collecting areas scattered all over the Pikes Peak region. The collecting localities range ...
"Imperial Porphyry" from the Red Sea Mountains of Egypt A waterworn cobble of porphyry Rhyolite porphyry from Colorado; scale bar in lower left is 1 cm (0.39 in). Porphyry (/ ˈ p ɔːr f ə r i / POR-fə-ree) is any of various granites or igneous rocks with coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate-rich, generally aphanitic matrix or groundmass.
These rocks (granite, rhyolite) are usually light coloured, and have a relatively low density. Intermediate rocks have a moderate content of silica, and are predominantly composed of feldspars. These rocks (diorite, andesite) are typically darker in colour than felsic rocks and somewhat more dense.
List of rocks on Mars – Alphabetical list of named rocks and meteorites found on Mars; Rock cycle – Transitional concept of geologic time; List of rock formations: for a list of unusual or culturally significant rock outcrops; Leaverite – Rock in the field that looks interesting but is actually not
Alkali feldspar granite, some varieties of which are called 'red granite', [1] is a felsic igneous rock and a type of granite rich in the mineral potassium feldspar (K-spar). It is a dense rock with a phaneritic texture. The abundance of K-spar gives the rock a predominant pink to reddish hue; peppered with minor amounts of black minerals. [2] [3]