Serpentine Mineral
CatgorieIX: silicates | |
|---|---|
 | |
| Category | Kaolinite |
| Empirical formula | (Mg, Fe, Ni) 3 Si 2 O 5 (OH) 4 |
| Color | green, brown, gray, blue-green, apple green, beige, yellow, black, white or colorless |
| Crystal system | triclinic, monoclinic |
| Cleavage | Net {001} |
| Habitus | fibrous masses small interstitial |
| Mohs | 2.5 to 3.5 |
| Brightness | vitreous, greasy or silky |
| Density | 2.55 to 3.30 |
| Magnetism | no |
| Radioactivity | no |
The serpentine is not a mineral species but a family group minerals of silicates subgroup of phyllosilicates (or layered silicate). This family contains 20 members or more polymorphic and that found in metamorphic rocks rich in hydrides of iron , Aluminium , Manganese , Nickel , Zinc , Calcium and / or magnesium ((Mg, Fe) 3 Si 2 O 5 ( OH) 4). Given their origin and transmutation that because of the many additives being present during this, its members are often difficult to identify because this mineral crystallizes also miscrocristaux. The 3 most important polymorphs of serpentine are the antigorine the chrysotile and lizardite. The rocks corresponding to the family of serpentine is the serpentinite.
Serpentine is used in jewelry as carved stone, or as an ornamental stone. The asbestiform habit can cause cancer.
Summary |
Etymology
Their coloration olive Ainis their soft and scaly appearance is the origin of the name of their original rocks, rocks ophidian from the Greek "ophidis" snake and form mineral serpentine, which comes from the Latin "serpentinus" which means snake stone. The generic term covers serpentine however a wide range of minerals are difficult to identify which generates many confusion in the literature of the nineteenth and even the first part of the twentieth century.
Gitology
These minerals derive their origins and metamorphoses of alterations in peridotite and pyroxene. Serpentines can also be pseudomorphs by other silicates of magnesium. The alterations may be incomplete and result in significant change in physical properties of serpentine also explain the large variety of its varieties. Serpentines occupy a significant proportion of the rocky mantle of the Earth, especially in areas unusually rich in clays. The antigorite is the polymorph of serpentine most common, resulting from the metamorphism of wet ultramafic rocks while remaining stable up to 600 C and at depths of 60 km or more. Instead of lizardite and chrysotile are the shapes from the superficial layers of the crust and which degrade at temperatures of about 400 C. It has been suggested that chrysotile would be no stability in total against the other two main polymorphs of serpentine. This could explain its harmfulness as carcinogenic agent. Samples from the seabed show that the ultramafic rocks are rich in serpentine. The antigorite contains water in its structure up to about 13% of its weight. It seems that antigorite may play a significant role in the phenomena of aqueous transport and the creation of underground volcanic islands and water fracture zones of tectonic plates also allowing water to reach great depths.
Soil Science
The solids from the breakdown of serpentine are toxic to many plants because of their high content of nickel , chromium and cobalt , growth of plants can also be found inhibited by high levels of potassium , phosphorus and an impoverishment Torque calcium / magnesium. The flora of these regions becomes very distinctive species with low growth. The serpentine areas are generally well shrubland (like bush ), an area of small trees, often conifers sometimes even in the middle of forest areas, these zones are referred to as the''serpentine's barren,''literally "sterile area serpentine "because of the contrast caused by the poisoning of plants in this area compared to other areas.
Physical properties
Most serpentines are opaque to translucent, light (density 2.2 to 2.9), soft (2.5-4), infusible (they go wrong they do not melt) and may prove to acids. All are microcrystalline and massive in habit, single crystals have never been observed. The luster is vitreous, greasy or silky. The color spectrum is varied, ranging from white to gray to blue, green and yellow to brown to black and often with aggregations or concentrations or veined. They are often present in mineral aggregates or inclusions but also include forms in plates or fibers. Their crystallization is so tiny and often invisible to the naked eye. However, as they may crystallize into long fibers, it is not uncommon to see them occupy the interstices rock as in the case of alpine slots in which they can reach several meters long fiber.
Occurrence in France
Serpentine deposits are those of the serpentinite.
- Puy de Volf to Firmi in the department of Aveyron , this massive serpentinite would be the largest of Europe.
- A deposit was exploited in the department of Isere on the massif of Tabor at a place called "La Chinard at the foot of the ski lifts of the resort of Alpe du Grand Serre. The career open opens on the side of the summit Chinard, the marble extracted varies from dark green to yellow green. The blocks were extracted from the neck down the Oullires to be cut in the marble Luyat Mure
Gems
Forms gems are cut as gems and stones ornamentals (the antigorite ). Often dyed, they may imitate jade and find himself appointed "Suzhou jade," "Styrian jade", "Teton jade" and "New jade". Serpentine of New Caledonia are particularly rich in nickel and one of the major sources of the world ore nickel ( Nepouite ).
The Bowenite and williamsite , varieties of antigorite are the most common varieties with lizardite for these uses. Their delicate colors, the translucent appearance but tender on galementleur make them attractive for sculpture or jewelry .
Species Group (polymorphs)
The first difficulty in describing this group is that, originally, it was considered a mineral available in several forms. The second comes from its metamorphic origin and its extremely complex formulas so that Dana and Strunz do not address the same way one puts it in combination with several minerals and other references associated with the serpentine kaolinite resulting in a complicated categorization with common , . The group is also clear that the classification of Dana, the classification of Strunz paying the serpentine in kaolinites.
Categorization of Dana
71.01.02a Serpentine Group
71.01.02a.01 antigorite (Mg, Fe + +) 3 Si 2 O 5 (OH) 4 Cm m polysomatic series where the trend typical of the serpentine curvature is reversed periodically, which results in a structure of corrugated ;
71.01.02b Subgroup of Lizardite
71.01.02b.01 Caryopilite (Mn + +, Mg, Zn, Fe + +) 3 (Si, As) 2 O 5? (OH, Cl) 4 Cm or C 2 / m Mono
71.01.02b.02 Lizardite Mg 3 Si 2 O 5 (OH) 4 P1 1, layer lines, where the silicon and magnesium are partially replaced by the aluminum ;
71.01.02b.03 garnierite ( Nepouite ) Ni 3 Si 2 O 5 (OH) 4 mm2 Ccm21
71.01.02b.04 Greenalite (Fe + +, Fe + + +) 2-3 Si 2 O 5 (OH) 4 Unk Mono
71.01.02c Subgroup of amesite
71.01.02c.01 amesite Mg 2 Al (SIAL) O 5 (OH) 4 C1 1
71.01.02c.02 berthierine (Fe + +, Fe + + +, Al, Mg) 2-3 (Si, Al) 2 O 5 (OH) 4 Cm m
71.01.02c.03 Brindleyite (Ni, Mg, Fe + +) 2 Al (SIAL) O 5 (OH) 4 C 2 2
71.01.02c.04 Fraipontite (Zn, Al) 3 (Si, Al) 2 O 5 (OH) 4 Cm m
71.01.02c.05 Kellyite (Mn + +, Mg, Al) 3 (Si, Al) 2 O 5 (OH) 4 P 63 6
71.01.02c.06 Manandonite Li 2 Al 471.01.02d subgroup of Chrysotile
71.01.02d.00 Chrysotile Mg 3 Si 2 O 5 (OH) 4 A2 / m 2 / m, the main VARIETIES of asbestos , layered curves that form spirals
71.01.02d.04 Pecoraite Ni 3 Si 2 O 5 (OH) 4 C 2 / m 2 / m
Clinochrysotile, Orthochrysotile Parachrysotile and were decommissioned by the IMA in 2006 and now defined as polytypes of Chrysotile Categorization of Nickel Strunz Group kaolinite-serpentine 09.ED Phyllosilicates structure with kaolinite Serpentine is since 1965 the mineral reference the state of California to the USA . Response to health problems because of asbestos, its removal has been requested since 2010 Gallery Chyta, Serpentine "leaf" ( antigorite ) Chrysotile electron microscope 
See also
Notes and References
Portal minerals and rocks
(1 votes, average: 4.00 out of 5, rated)
Loading ...