Feldspathoid - Wikipedia
The feldspathoids are a group of tectosilicate minerals which resemble feldspars but have a different structure and much lower silica content. They occur in rare and unusual types of igneous rocks, and are usually not found in rocks containing primary quartz.
Feldspathoid | Mineral Composition, Uses & Characteristics
Feldspathoid, any of a group of alkali aluminosilicate minerals similar to the feldspars in chemical composition but either having a lower silica-alkali ratio or containing chloride, sulfide, sulfate, or carbonate. They are considered to be the specific minerals of igneous rocks usually termed
似长石 - 维基百科，自由的百科全书
似长石（feldspathoid）是一组类似长石，但结构不同，二氧化硅含量低得多的网硅酸盐 矿物。 它们出现在罕见的 火成岩 中，通常在主要含 石英 的岩石中找不到，但一则值得注意的例外是，在红山岩（Red Hill Syenite） 正长岩 中同时发现了似长石和含石英岩石 [ 1 ] 。
似长石 - 百度百科
似长石（feldspathoid）是指化学组成与长石相似，金属阳离子为钾、钠或钙，但Si/Al比值小于3的一些无水架状结构 铝硅酸盐矿物 的总称。 具架状骨干硅盐矿物有如霞石族、 白榴石 族、方钠石族、日光榴石族和方柱石族等，他们一般统称为 似长石矿物。 因为它们与 长石矿物 相似，同为不含水的架状结构硅酸盐。 [1] 似长石也称 副长石。 包括霞石、 白榴石 、 方柱石 、 钙霞石 和方钠石等。 它们都产出在富含碱质而贫于硅的条件下，不与石英共生。 其中以霞石和白榴石最为重 …
Feldspathoids - Geology is the Way
Feldspathoids or foids are a family of rock-forming alkali-bearing aluminosilicates that form only in silica-undersaturated igneous rocks. The name derives from their chemical (and sometimes structural) similarity with feldspars.
feldspathoid summary | Britannica
feldspathoid , Any of a group of alkali aluminosilicate minerals similar to the feldspars in composition but having a lower silica-alkali ratio or containing chloride, sulfide, sulfate, or carbonate. Their physical and chemical properties lie between those of the feldspars and zeolites.
6.4.4: Feldspathoids - Geosciences LibreTexts
2022年12月16日 · Feldspathoids are a family of about a dozen minerals; they are all Na-, K-, and Ca-aluminosilicates. The family is not like other mineral groups, whose members are related by similar atomic arrangements and chemistries. Instead these minerals are grouped together because of their relationship to feldspars.
Chemistry, Occurrence and Paragenesis of Feldspathoids: A Review …
Feldspathoids are a loosely-defined group of alkali alumino silicate minerals deficient in SiO 2 with respect to feldspars.
Feldspathoid group - SpringerLink
The minerals nepheline, kalsilite, and leucite comprise the feldspathoid group. They have framework structures of silicon (SiO 4) and tetrahedra and crystallize in silica-poor environments.
Feldspars and Feldspathoids - Springer
The feldspars form the most abundant group of minerals in the crust of the Earth and Moon and also occur in many meteo rites. They playa fundamental role in all rock-forming processes at shallow depths, but are rare or absent from the upper mantle.