Search results
Results from the WOW.Com Content Network
Bowenite, a variety of antigorite, is an especially hard serpentine (5.5) of light to dark apple green color, often mottled with cloudy white patches and darker veining. It is the serpentine most frequently encountered in carving and jewelry. The name 'retinalite' is sometimes applied to yellow bowenite. The New Zealand material is called tangiwai.
The mixture of brucite and serpentine formed by Reaction 1b has the lowest silica activity in the serpentinite, so that the brucite phase is very important in understanding serpentinization. [14] However, the brucite is often blended in with the serpentine such that it is difficult to identify except with X-ray diffraction , and it is easily ...
Serpentine group minerals have a Mohs hardness of 2.5 to 3.5, so serpentinite is easily carved. [26] Grades of serpentinite higher in calcite , along with the verd antique ( breccia form of serpentinite), have historically been used as decorative stones for their marble-like qualities.
Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially antigorite, lizardite, and chrysotile or white asbestos, all of which are commonly found in ultramafic ...
Polished slab of bowenite serpentine, a variety of antigorite.. Bowenite is a hard, compact variety of the serpentinite species antigorite (Mg 3 (OH)O 4 Si 2 O 5). [1] Classed as a semi-precious gemstone, [2] it has been used for tools, weapons and jewellery by the Māori in New Zealand, [3] [4] and for jewellery by Fabergé. [5]
Antigorite, and its serpentine polymorphs, play an important role in subduction zone dynamics due to their relative weakness and high weight percent of water (up to 13 weight % H 2 O). [ 3 ] [ 4 ] It is named after its type locality, the Geisspfad serpentinite, Valle Antigorio in the border region of Italy / Switzerland [ 5 ] and is commonly ...
Strongly deformed and serpentinized rocks appear marble-like due to interchanging dark green and light green areas. Crosscutting veins are mainly mineralized by serpentine minerals (like cross fibers of chrysotile) and magnetite. Under the microscope the following minerals can be identified: antigorite; chrysotile
Talc dominantly forms from the metamorphism of magnesian minerals such as serpentine, pyroxene, amphibole, and olivine, in the presence of carbon dioxide and water. This is known as "talc carbonation" or "steatization" and produces a suite of rocks known as talc carbonates .