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QAPF diagram for classification of plutonic rocks. A QAPF diagram is a doubled-triangle plot diagram used to classify intrusive igneous rocks based on their mineralogy.The acronym QAPF stands for "Quartz, Alkali feldspar, Plagioclase, Feldspathoid (Foid)", which are the four mineral groups used for classification in a QAPF diagram.
When using the chart, it is important to remember these tips: Isotropic and opaque (metallic) minerals cannot be identified this way. The stage of the microscope should be rotated until maximum colour is found, and therefore, the maximum birefringence. Each mineral, depending on the orientation, may not exhibit the maximum birefringence.
Diorite is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and sometimes pyroxene.The chemical composition of diorite is intermediate, between that of mafic gabbro and felsic granite.
The minerals in a phaneritic igneous rock are sufficiently large to see each individual crystal with the naked eye. Examples of phaneritic igneous rocks are gabbro , diorite , and granite . Porphyritic textures develop when conditions during the cooling of magma change relatively quickly.
Diorite – Igneous rock type Napoleonite, also known as corsite – Variety of diorite with orbicular structure; Dunite – Ultramafic and ultrabasic rock from Earth's mantle which is made of the mineral olivine; Essexite – Igneous rock type; Foidolite – Igneous rock rich in feldspathoid minerals; Gabbro – Coarse-grained mafic intrusive rock
This is a list of minerals which have Wikipedia articles.. Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various species.
Napoleonite is a variety of diorite which is characterized by orbicular structure. The grey matrix of the stone has the normal appearance of a diorite, but contains many rounded lumps 1 or 2 inches in diameter, which show concentric zones of light and dark colors.
Quartz diorite from Dúbrava, Nízke Tatry Mountains, Slovakia. Quartz diorite is an igneous, plutonic rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less potassium feldspar. Quartz is present at between 5 and 20% of the rock.