Serpentine Type

[Mina]

Serpentinesubgroup (part of the kaolinite-serpentine group in the category of phyllosilicates)[1] are greenish, brownish, or spotted minerals commonly found in serpentinite. They are used as a source of magnesium and asbestos, and as decorative stone.[5] The name comes from the greenish color and smooth or scaly appearance from the Latin serpentinus, meaning "snake-like".

Serpentine subgroup is a set of common rock-forming hydrous magnesium iron phyllosilicate ((Mg,Fe)

3Si

2O

5(OH)

4) minerals, resulting from the metamorphism of the minerals that are contained in mafic to ultramafic rocks.[6] They may contain minor amounts of other elements including chromium, manganese, cobalt or nickel. In mineralogy and gemology, serpentine may refer to any of the 20 varieties belonging to the serpentine subgroup. Owing to admixture, these varieties are not always easy to individualize, and distinctions are not usually made. There are three important mineral polymorphs of serpentine: antigorite, lizardite and chrysotile.

Serpentine minerals are polymorphous, meaning that they have the same chemical formulae, but the atoms are arranged into different structures, or crystal lattices.[7] Chrysotile, which has a fibrous habit, is one polymorph of serpentine and is one of the more important asbestos minerals. Other polymorphs in the serpentine subgroup may have a platy habit. Antigorite and lizardite are the polymorphs with platy habit.

Samples of the oceanic crust and uppermost mantle from ocean basins document that ultramafic rocks there commonly contain abundant serpentine. Antigorite contains water in its structure, about 13 percent by weight. Hence, antigorite may play an important role in the transport of water into the earth in subduction zones and in the subsequent release of water to create magmas in island arcs, and some of the water may be carried to yet greater depths.

Serpentines find use in industry for several purposes, such as railway ballasts, building materials, and the asbestiform types find use as thermal and electrical insulation (chrysotile asbestos). The asbestos content can be released into the air when serpentine is excavated and if it is used as a road surface, forming a long-term health hazard by breathing. Asbestos from serpentine can also appear at low levels in water supplies through normal weathering processes, but there is as yet no fully proven health hazard associated with use or ingestion, although the EPA states an increased risk of developing benign intestinal polyps can occur.[17] In its natural state, some forms of serpentine react with carbon dioxide and re-release oxygen into the atmosphere.

The more attractive and durable varieties (all of the antigorite) are termed "noble" or "precious" serpentine and are used extensively as gems and in ornamental carvings. The town of Bhera in the historic Punjab province of the Indian subcontinent was known for centuries for finishing a relatively pure form of green serpentine obtained from quarries in Afghanistan into lapidary work, cups, ornamental sword hilts, and dagger handles.[9] This high-grade serpentine ore was known as sang-i-yashm in Persian, or 'false jade' in English, and was used for generations by Indian craftsmen for lapidary work.[9][18] It is easily carved, taking a good polish, and is said to have a pleasingly greasy feel.[19] Less valuable serpentine ores of varying hardness and clarity are also sometimes dyed to imitate jade.[19] Misleading synonyms for this material include "Suzhou jade", "Styrian jade", and "New jade".

The lapis atracius of the Romans, now known as verde antique, or verde antic, is a serpentinite breccia popular as a decorative facing stone. In classical times it was mined at Casambala, Thessaly, Greece. Serpentinite marbles are also widely used: Green Connemara marble (or 'Irish green marble') from Connemara, Ireland (and many other sources[citation needed]), and red Rosso di Levanto marble from Italy. Use is limited to indoor settings as serpentinites do not weather well.

Soils derived from serpentine are toxic to many plants, because of high levels of nickel, chromium, and cobalt; growth of many plants is also inhibited by low levels of potassium and phosphorus and a low ratio of calcium/magnesium. The flora is generally very distinctive, with specialized, slow-growing species. Areas of serpentine-derived soil will show as strips of shrubland and open, scattered small trees (often conifers) within otherwise forested areas; these areas are called serpentine barrens.

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.

Although not an official species, bowenite is the state mineral of Rhode Island, United States: this is also the variety's type locality. A bowenite cabochon featured as part of the "Our Mineral Heritage Brooch", was presented to U.S. First Lady Mrs. Lady Bird Johnson in 1967.

Williamsite is an American local varietal name for antigorite that is oil-green with black crystals of chromite or magnetite often included. Somewhat resembling fine jade, williamsite is cut into cabochons and beads. It is found mainly in Maryland and Pennsylvania.[20]

When it comes to industrial hot oil heaters and thermal fluid heaters, there are many options and varieties to choose from. With so many options, the process of determining which heating product or system is most appropriate for your business can feel daunting.

Most industrial heating equipment manufacturers solely produce thermal fluid heaters that feature helical heating coils. While we do produce helical coil thermal fluid heaters for clients in need of this specific type of equipment, the majority of thermal fluid heaters we produce feature serpentine coil technology. In fact, our standard thermal fluid heaters are designed and equipped with the more efficient, durable serpentine coil technology.

While helical coil heaters feature helically wound coils, our serpentine coil heaters feature serpentine radiant coil bundles. The difference between the two coil types can be seen in the cross-section images below.

In the radiant section of the heater (A), heat is transferred to the front, sides and back of the serpentine coil. This allows for more even heat distribution, less coil degradation, longer tube life, and higher operating oil temperatures. In the convection section (B) of our serpentine coil, heat is transferred to a much larger surface area in our integrated economizer. This reduces stack temperature and makes the serpentine coil hot oil heater 10-15% more efficient.

In the radiant section of the heater (A), heat is transferred by direct radiation only on the inside surface of the helical coil. Convection (B) only occurs as the vapors pass over the outside surface of the helically wound coils, before leaving the stack at a much higher temperature. Although less efficient, this design is more compact. These, and other, factors set serpentine coil thermal fluid heaters apart from typical hot oil heaters and enable them to provide a number of benefits.

Higher Efficiency: Serpentine coil heaters are 10 to 15% more efficient than hot oil heaters that feature helical coils. As an example, when switching from a helical to a serpentine coil thermal fluid heater with a maximum load of 2MM Btu/hr, the fuel cost savings per year can be upwards of $270,000. The fuel savings in one to two years will pay for the equipment itself!

Higher Operating Temperatures: Typical hot oil heaters offer limited operation at fluid temperatures over 400F, but serpentine coil hot oil heaters can operate efficiently at temperatures up to 650F.

Have questions specific to your industry or application? Give us a call today at (715) 748-5888 or contact us online to learn more about our hot oil heaters and the other industrial heating products we offer.

Fike, J. 1999. Terrestrial and palustrine plant communities of Pennsylvania. Pennsylvania Natural Diversity Inventory. Pennsylvania Department of Conservation and Recreation, Bureau of Forestry, Harrisburg, PA. 86 pp.

This community is distinguished from other types of seeps primarily by its landscape context. This type occurs exclusively in areas underlain by serpentinite bedrock and influenced by groundwater rich in calcium, magnesium, chromium, nickel, and iron.

Alteration to the hydrological regime and development are the major threats to this community and can lead to habitat destruction and/or shifts in community function and dynamics. Clearing and development of adjacent land can lead to an accumulation of agricultural run-off and pollution, and sedimentation. This community is limited to areas where serpentine bedrock is near the surface, resulting in a limited range of potential habitats.

Extraction, drilling, mining, or other activities that impact the bedrock or flow of groundwater should not be undertaken within half a mile of a seepage wetland without a thorough understanding of bedrock layers and groundwater flows. A natural buffer around the wetland should be maintained in order to minimize nutrient runoff, pollution, and sedimentation. The potential for soil erosion based on soil texture, condition of the adjacent vegetation (mature forests vs. clearcuts), and the topography of the surrounding area (i.e., degree of slope) should be considered when establishing buffers. The buffer size should be increased if soils are erodible, adjacent vegetation has been logged, and the topography is steep as such factors could contribute to increased sedimentation and nutrient pollution. Direct impacts and habitat alteration should be avoided (e.g., roads, trails, filling of wetlands) and low impact alternatives (e.g., elevated footpaths, boardwalks, bridges) should be utilized in situations where accessing the wetland can not be avoided. Care should also be taken to control and prevent the spread of invasive species within the wetland.

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