What is the difference between antigorite and chrysotile?
species, chrysotile, antigorite, and lizardite are commonly known; the formula of these three clay minerals is Mg3Si2O5(OH)4. Chrysotile crystals have a cylindrical roll morphology, while antigorite crystals exhibit an alternating wave structure.
What is antigorite serpentine?
Antigorite is a lamellated, monoclinic mineral in the phylosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinites.
How is antigorite formed?
Antigorite belongs to the group of trioctahedral 1:1 layered silicates, consisting of one tetrahedral (T) and one octahedral (O) sheet. The T sheet is formed by the two-dimensional polymerization of Si-centered tetrahedra sharing three out of four oxygen atoms with other tetrahedra.
Is antigorite a silicate?
Antigorite [(Mg,Fe)3Si2O5(OH)4] is a hydrous magnesium iron member of the serpentine subgroup with alternating polymerized silicate and brucite-like magnesium octahedral layers.
What type of crystal is serpentine?
magnesium silicate minerals
Serpentine is actually a group of magnesium silicate minerals, which are related but have different structures. All variations of serpentine are a basic magnesium silicate, with many containing iron as well. Serpentine may also contain smaller quantities of elements such as chromium, nickel and cobalt.
Where is serpentine formed?
tectonic plate boundaries
Serpentinite is a metamorphic rock that forms at tectonic plate boundaries deep within the Earth.
How is lizardite formed?
Formation. Lizardite is commonly a result from the hydrothermal metamorphism or retrograde metamorphism of mafic minerals such as olivine, pyroxene or amphibole, in ultrabasic rocks.
Is lizardite a sheet silicate?
Lizardite is a serpentine group mineral of the phyllosilicate class of silicates. It is a 1:1 trioctahedral phyllosilicate (clay) mineral. The tetrahedral sheet is mainly dominated by Si and the octahedral sheet is dominated by Mg in the lizardite end member.
What is the difference between serpentine and nephrite?
»Nephrite« can be confused especially with serpentine. Both the (fatty) luster (Fig. 2) and the fibrous structure are confusingly similar. However, the density of serpentine minerals is only 2.4 to a maximum of 2.8, making any serpentine mineral reliably distinguishable from »Nephrite« and jadeite.
What is mineral glauconite?
Glauconite is an iron potassium phyllosilicate (mica group) mineral of characteristic green color which is very friable and has very low weathering resistance.
What is the mineral composition of serpentine?
Serpentine rock is primarily composed of one or more of the three magnesium silicate minerals, “lizardite,” “chrysotile,” and “antigorite.” Chrysotile often occurs as fibrous veinlets in serpentine. Chrysotile in fibrous form is the most common type of asbestos.
How is antigorite structurally distinct?
Antigorite is structurally distinct in having a large a cell parameter of ∼33–51 Å, which can be related to the curvature of serpentine layers about y and their inversion to form a corrugated sheet structure with periodicity a ( Figure 7 ). Figure 6. The crystal structure of antigorite as viewed along the y -axis.
What is the difference between nonasbestiform and Asbestiform amphibole crystals?
The asbestiform varieties of amphiboles have essentially the same crystal structure as the nonasbestiform varieties. Figure 2-3 shows schematically the structure of amphibole crystals looking down the silica chains.
What are asbestiform fibers?
Unlike many environmental substances that are discrete entities definable by a fixed chemical structure, asbestiform fibers comprise a group of materials that are less easily defined. They have a broad range of chemical compositions and crystal structures, sizes, shapes, and properties, and have been described with diverse terminology.
What is the crystalline structure of asbestos?
The most common asbestos, chrysotile, is a member of the serpentine group. Because of their layered silicate structure, serpentine minerals usually crystallize as thin platy crystals; however, some of them, e.g., chrysotile, occasionally crystallize as thin hairlike fibers.