Soapstones

Soapstones

One of our subjects on this semester was about the Earth Science. Our professor told us to make a weekly blog post about anything related to Earth Science.

First, I would like to define first, what is Earth Science. Earth science (also known as geoscience, the geosciences or the Earth sciences) is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences. The formal discipline of Earth sciences may include the study of the atmosphere, hydrosphere, oceans and biosphere, as well as the solid earth. Typically Earth scientists will use tools from physics, chemistry, biology, chronology and mathematics to build a quantitative understanding of how the Earth system works, and how it evolved to its current state.

In short, Earth Science encompasses all sciences that seek to understand Earth and its neghbors in space that has 4 major branches: Geology (Study of the Earth (Solid acpects)), Oceanography (Study of the Ocean), Meteorology (Study of the Atmosphere and the processes that prodduce weather), and Astronomy (The study of the Universe).

One of the places I want to visit was Brazil because of their festivals, the beach, and the landmark Cristo Redentor. Cristo Redentor (Christ the Redeemer) is a statue of Jesus Christ in Rio de Janeiro, Brazil; considered the largest Art Deco statue in the world and the 5th largest statue of Jesus in the world. It is 39.6 metres (130 ft) tall, including its 9.5 metres (31 ft) pedestal, and 30 metres (98 ft) wide. It weighs 635 tonnes (625 long,700 short tons), and is located at the peak of the 700-metre (2,300 ft) Corcovado mountain in the Tijuca Forest National Park overlooking the city. A symbol of Brazilian Christianity, the statue has become an icon for Rio de Janeiro and Brazil. It is made of reinforced concrete and soapstone, and was constructed between 1922 and 1931.

This statue leads my curiosity to research about Soapstone.

The outer layers of the Christ the Redeemer sculpture are made of soapstone.

Soapstone

Soapstone is quarried like Granite and Marble. It is a steatite stone and its primary components are magnesite, dolomite, chlorite, and talc[Mg3Si4O10(OH)2]. It can range in age from 300 to 400 million years old depending on which part of the planet it is drawn from. As talc in soapstone is soft to the touch, it gives the smooth feeling of rubbing a piece of dry soap. Thus the name was derived – “Soap” Stone.
Soapstone is typically gray, bluish, green or brown in color, often variegated. Some soapstones are micro- or cryptocrystalline. Its mineral composition can vary. Its composition depends upon the parent rock material and the temperature/pressure conditions of its metamorphic environment. As a result, the physical properties of the soapstone can vary from quarry to quarry and even within a single rock unit.
Properties of talc:

• Colors – white, gray, greenish gray, pale green — commonly discolored in reddish or brownish hues and mottled
• H. 1 (but, because of the presence of impurities, effective hardness of soapstone may range up to 7)
• S.G. 2.5-2.8
• Light transmission – translucent to opaque
• Luster – waxy to pearly
• Miscellany – feels greasy or soapy. Some soapstone contains noteworthy percentages of pyrophyllite, which is virtually indistinguishable from talc by macroscopic means. Other relatively common constituents of soapstone, which may or may not be macroscopically discernible, are chlorite, dolomite, magnesite, tremolite and minor amounts of oxides such as magnetite and chromite and even rare sulfides.

Properties of Soapstone:

• soft and very easy to carve
• non-porous
• non-absorbent
• low electrical conductivity
• heat resistant
• high specific heat capacity
• resistant to acids and alkalis

Other names

• Agalmatolite – some agalmatolite is soapstone.
• Combarbalite – name given to varicolored (e.g., diverse red, green, yellow, and brown hues) soapstone from vicinity of Combarbala in the Andean foothills of Coquimbo Province, Chile.
• Gorara stone – ill-defined “soft stone” — also referred to as India soapstone and sometimes, apparently incorrectly, as gorara marble — reportedly from Hamipur and Mahoba areas of Uttar Pradesh, India; colors, commonly mottled, include gray, pink, green, tan and black.
• Honan jade – a marketplace misnomer.
• Image stone – name given to some steatite from India.
• Manchurian jade – a marketplace misnomer.
• Neolite – marketplace name once used for steatite.
• Pagodaite
• Palewa soapstone – tan, green, gray (which is darkened when hand polished) soapstone that has been carved for several decades in Agra, India, site of the famous Taj Mahal.
• Pearlescent soapstone – vaguely descriptive designation given soapstones of diverse colors marketed as carved “bowls” made explicitly for aromatic and votive candles.
• Potstone – a marketplace name applied to steatite, especially that fashioned into vessels for heating, for example, water for tea.
• Pratima culler – name given to some steatite from India.
• Rapoka – name given rock, which are soapstone-like, rather widely marketed as carvings fashioned in Zimbabwe. Some of the materials so-identified may be serpentine rather than soapstone.
• Steatite – a widley used synonym of soapstone, as is indicated by the entry subtitle.
• Suzhou jade – a marketplace misnomer.

The term steatite is sometimes used for soapstone. It is often used as an insulator or housing for electrical components, due to its durability and electrical characteristics and because it can be pressed into complex shapes before firing. Steatite undergoes transformations when heated to temperatures of 1000–1200 °C into enstatite and cristobalite; in the Mohs scale, this corresponds to an increase in hardness from 1 to 5.5–6.5.

Formation

Soapstone are most often formed at the convergent plate boundaries where broad areas of Earth’s crust are subjected to heat and directed pressure. Peridotites, dunites and serpentinites in this environment can be metamorphosed into soapstone. On a smaller scale soapstone can form where siliceous dolostones are altered by hot, chemically-active fluids in a process known as metasomatism.

It is produced by dynamothermal metamorphism and metasomatism, which occurs in the areas wheretectonic plates are subducted, changing rocks by heat and pressure, with influx of fluids, but without melting. It has been a medium for carving for thousands of years.

History

People have quarried soapstone for thousands of years. Native Americans in eastern North America used the soft rock to make bowls, cooking slabs, smoking pipes and ornaments as early as the Late Archaic Period. It is also used on making seals, especially in ancient times. Since it can be easily carved, it was sculpted into, for example, busts too at least as early as 2550 B.C

The people of Scandinavia began using soapstone during the Stone Age and it helped them enter the Bronze Age when they discovered that it could be easily carved into molds for casting metal objects such as knife blades and spearheads.

Uses

For thousands of years, soapstone has been used throughout the world for tools. In early American history, soapstone was used primarily for building blocks, sculpting and urns. It was also used in building home structures, a popular choice for the do-it-all sink because it could be easily cut to shape with non stone cutting tools. It can be used too in high-frequency insulators in such things as radios. The soapstone can slowly radiate heat too very evenly for hours on end (even after the fire has long gone out). It could transmit and retain heat without breaking and consequently could be used in cooking. Other uses:

• Fireplace hearths, fireplace liners
• Counter top, island tops, sinks
• Oven, stoves, (could grill without using any grease), cook-tops, cookware, oven baking decks, cooking slabs, boiling stones
• Carafes, goblets,
• Mixing bowls, cooking pots,
• Vases, pottery, bowls, plates
• Ornamental carvings and sculptures
• Balusters, stair treads, window sills
• Mitten shaped soapstone (for heating mittens)
• Cemetery markers
• Electrical panels
• Wall tiles and floor tiles, facing stone
• Molds for metal casting
• Cold stones
• Pieces tailors used to mark clothing for alteration, Slate pencils

 

Conclusion  

Learning about soapstones gives artist/art students like me new ideas on what materials we could use in making artworks by familiarizing on each material one by one. We can take this idea as a recommendation or suggestion on what else we can  use, and this is how I think this blog post will contribute to the net, especially in merging Art with Earth Science.

Myikc Tsoerr, 3AD8

———–Sources———-

• http://en.wikipedia.org/wiki/Earth_science
• http://en.wikipedia.org/wiki/Christ_the_Redeemer_(statue)
• http://www.soapstone-co.com/whatis101.html
• http://geology.com/rocks/soapstone.shtml
• http://en.wikipedia.org/wiki/Soapstone
• http://stoneplus.cst.cmich.edu/soapstone.htm
• https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_111461.htm
• http://antiquity.ac.uk/ProjGall/shaffer/shaffer.html

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Checked by Prof. Crisencio Paner