feldspars
21Mineral — For other uses, see Mineral (disambiguation). An assortment of minerals. A mineral is a naturally occurring …
22Orthoclase — General Category Silicate mineral Chemical formula KAlSi3O8 …
23Microcline — Optical properties Microcline Microcline feldspar Crystal System: Triclinic Color in PPL …
24Porcelain — Fine China redirects here. For the band, see Fine China (band). This article is about the ceramic material. For other uses, see Porcelain (disambiguation). Chinese moon flask, 1723 35, Qing Dynasty …
25Trachyte — is an igneous, volcanic rock with an aphanitic to porphyritic texture. The mineral assemblage consists of essential alkali feldspar; relatively minor plagioclase and quartz or a feldspathoid such as nepheline may also be present. (See the QAPF… …
26Nepheline syenite — of the Intrusive Complex of Tanguá, State of Rio de Janeiro, Brasil (Motoki et al., 2011a) Nephelene syenite is a holocrystalline plutonic rock that consists largely of nepheline and alkali feldspar. The rocks are mostly pale colored, grey or… …
27Scapolite — (Gr. asairos , rod, stone), is a group of rock forming silicate minerals composed of aluminium, calcium and sodium silicate with chlorine, carbonate and sulfate. The variations in composition of the different members of the group may be expressed …
28Variolite — Variolites (Latin varius , speckled, variegated ) are a group of dark green basic igneous rocks that, especially on weathered surfaces, exhibit pale colored spots, or spherules, that give them a pockmarked appearance. In some conditions these… …
29Lamprophyre — Lamprophyres (Greek λαµπρός (lamprós) = bright and φύρω (phýro) = to mix) are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica… …
30Quartz-porphyry — Quartz porphyry, in petrology, is the name given to a group of hemi crystalline acid rocks containing porphyritic crystals of quartz in a fine grained matrix, usually of micro crystalline or felsitic structure. In specimens, the quartz appears as …
