What minerals are feldspathoids?

What minerals are feldspathoids?

The feldspathoid are family of rock-forming minerals consisting of aluminosilicates of sodium, potassium, or calcium and having too little silica to form feldspar.

Where can Andradite be found?

Andradite is common and widespread, and good material can be found in Italy, Romania, Switzerland, Norway, South Africa, Russia, the United States, and Mexico.

How is brucite formed?

Brucite (Mg(OH)2) has an hexagonal structure (space group Pm1). It is often formed from the alteration of periclase (MgO) in Mg-bearing limestones and dolomites. These occurrences can be due to low-temperature hydrothermal alteration or metamorphism of limestones and schists and during the serpentinization of dunite.

Where do feldspathoids form?

In general, Na-feldspathoids occur in sodic magmas, whereas leucite and other K-bearing feldspathoids are more common in potassic and ultrapotassic rocks. More rarely, feldspathoids such as haüyne and nepheline may form in contact metamorphosed and metasomatized limestone close to igneous bodies.

What is a zeolite mineral?

zeolite, any member of a family of hydrated aluminosilicate minerals that contain alkali and alkaline-earth metals. The zeolites are noted for their lability toward ion-exchange and reversible dehydration.

Is andradite a gem?

Andradite is a common mineral but is usually opaque and not fit for gemstone use; the transparent gemmy forms are rare and valued. The term Andradite is strictly a mineral term and is rarely used in the gem market. The gem forms of Andradite are known by their variety names of Demantoid, Topazolite, and Melanite.

Is andradite garnet rare?

Andradite is one of the most sought after garnet species. Although more sources have been discovered in recent decades, gem-quality andradites remain rare.

Is peridot a forsterite?

As peridot is a magnesium-rich variety of olivine (forsterite), the formula approaches Mg2SiO4. Its green color is dependent on the iron contents within the structure of the gem. Peridot occurs in silica-deficient rocks such as volcanic basalt and pallasitic meteorites.

What is brucite used for?

Brucite is a mineral that is not often used as a mineral specimen but does have some important industrial uses. It is a minor ore of magnesium metal and a source of magnesia. It is also used as an additive in certain refractories. It is brucite’s structure that is interesting.

What is brucite mineral?

brucite, mineral composed of magnesium hydroxide, Mg(OH)2. It generally forms soft, waxy to glassy, white or pale-green, gray, or blue crystals, plate aggregates, or fibrous masses associated with other magnesium minerals (e.g., magnesite and dolomite).