Iodised salt is table salt mixed with a minute amount of various salts of the element iodine. The ingestion of iodine prevents iodine deficiency. Worldwide, iodine deficiency affects about two billion people and is the leading preventable cause of intellectual and developmental disabilities. Deficiency causes thyroid gland problems, including "endemic goitre". In many countries, iodine deficiency is a major public health problem that can be cheaply addressed by purposely adding small amounts of iodine to the sodium chloride salt. Iodine is a micronutrient and dietary mineral, present in the food supply in some regions near sea coasts, but is quite rare in the Earth's crust, since iodine is a so-called heavy element, abundance of chemical elements declines with greater atomic mass. Where natural levels of iodine in the soil are low and the iodine is not taken up by vegetables, iodine added to salt provides the small but essential amount of iodine needed by humans. An opened package of table salt with iodide may lose its iodine content through the process of oxidation and iodine sublimation.
Four inorganic compounds are used as iodide sources, depending on the producer: potassium iodate, potassium iodide, sodium iodate, sodium iodide. Any of these compounds supplies the body with its iodine required for the biosynthesis of thyroxine and triiodothyronine hormones by the thyroid gland. Animals benefit from iodine supplements, the hydrogen iodide derivative of ethylenediamine is the main supplement to livestock feed. Salt is an effective vehicle for distributing iodine to the public because it does not spoil and is consumed in more predictable amounts than most other commodities. For example, the concentration of iodine in salt has increased in Switzerland: 3.75 mg/kg in 1952, 7.5 mg/kg in 1962, 15 mg/kg in 1980, 20 mg/kg in 1998, 25 mg/kg in 2014. These increases were found to improve iodine status in the general Swiss population. Salt, iodised with iodide may lose its iodine content by exposure to excess air over long periods. Edible salt can be iodised by spraying it with a potassium potassium iodide solution.
57 grams of potassium iodate, costing about US$1.15, is required to iodise a ton of salt. Dextrose is added as a stabilizer to prevent potassium iodide from evaporating. Anti-caking agents such as calcium silicate are added to table salt to prevent clumping. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual and developmental disabilities. According to public health experts, iodisation of salt may be the world's simplest and most cost-effective measure available to improve health, only costing US$0.05 per person per year. At the World Summit for Children in 1990, a goal was set to eliminate iodine deficiency by 2000. At that time, 25% of households consumed iodised salt, a proportion that increased to 66% by 2006. Salt producers are although not always, supportive of government initiatives to iodise edible salt supplies. Opposition to iodisation comes from small salt producers who are concerned about the added expense, private makers of iodine pills, concerns about promoting salt intake, unfounded rumours that iodisation causes AIDS or other illnesses.
The United States Food and Drug Administration recommends 150 micrograms of iodine per day for both men and women. Since 8 May 1967 salt for human or animal use must be iodised, according to the Law 17,259. Australian children were identified as being iodine deficient in a survey conducted between 2003 and 2004 As a result of this study the Australian Government mandated that all bread with the exception of "organic " bread must use iodised salt. There remains concern that this initiative is not sufficient for lactating women. Iodine Deficiency Disorders were detected as a major public health issue by Brazilian authorities in the 1950s, when about 20% of the population had goiter; the National Agency for Sanitary Vigilance is responsible for setting the mandatory iodine content of table salt. The Brazilian diet averages 12 g of table salt per day, more than twice the recommended value of 5 g a day. To avoid excess consumption of iodine, the iodizing of Brazilian table salt was reduced to 15–45 mg/kg in July 2013.
Specialists criticized the move, saying that it would be better for the government to promote reduced salt intake, which would solve the iodine problem as well as reduce the incidence of high blood pressure. Salt sold to consumers in Canada for table and household use must be iodized with 0.01% potassium iodide. Sea salt and salt sold for other purposes, such as pickling, may be sold uniodized. Much of the Chinese population lives inland, far from sources of dietary iodine. In 1996, the Ministry of Public Health estimated that iodine deficiency was responsible for 10 million cases of mental retardation in China; the Chinese government had held a legal monopoly on salt production since 119 BCE and began iodizing salt in the 1960s, but market reforms in the 1980s led to widespread smuggling of non-iodized salt from private producers. In the inland province of Ningxia, only 20% of salt consumed was sold by the China National Salt Industry Corporation; the Chinese government responded by cracking down on smuggled salt, establishing a salt police with 25,000 officers to enforce the salt monopoly.
Consumption of iodized salt reached 90% of the Chinese population by 2000. Iodised salt was introduced to India in the late 1950s. Public awareness was increased by special programs and initiatives, both governmental and nongovernmental; as of now iodine deficiency is only present in a few isolated regions which are still unreachable
Salt is a mineral composed of sodium chloride, a chemical compound belonging to the larger class of salts. Salt is present in vast quantities in seawater; the open ocean has about 35 grams of solids per liter of sea water, a salinity of 3.5%. Salt is essential for life in general, saltiness is one of the basic human tastes. Salt is one of the oldest and most ubiquitous food seasonings, salting is an important method of food preservation; some of the earliest evidence of salt processing dates to around 6,000 BC, when people living in the area of present-day Romania boiled spring water to extract salts. Salt was prized by the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites and the Indians. Salt became an important article of trade and was transported by boat across the Mediterranean Sea, along specially built salt roads, across the Sahara on camel caravans; the scarcity and universal need for salt have led nations to go to war over it and use it to raise tax revenues. Salt has other cultural and traditional significance.
Salt is processed from salt mines, by the evaporation of seawater and mineral-rich spring water in shallow pools. Its major industrial products are caustic chlorine. Of the annual global production of around two hundred million tonnes of salt, about 6% is used for human consumption. Other uses include water conditioning processes, de-icing highways, agricultural use. Edible salt is sold in forms such as sea salt and table salt which contains an anti-caking agent and may be iodised to prevent iodine deficiency; as well as its use in cooking and at the table, salt is present in many processed foods. Sodium is an essential nutrient for human health via its role as an osmotic solute. Excessive salt consumption may increase the risk of cardiovascular diseases, such as hypertension, in children and adults; such health effects of salt have long been studied. Accordingly, numerous world health associations and experts in developed countries recommend reducing consumption of popular salty foods; the World Health Organization recommends that adults should consume less than 2,000 mg of sodium, equivalent to 5 grams of salt per day.
All through history, the availability of salt has been pivotal to civilization. What is now thought to have been the first city in Europe is Solnitsata, in Bulgaria, a salt mine, providing the area now known as the Balkans with salt since 5400 BC; the name Solnitsata means "salt works". While people have used canning and artificial refrigeration to preserve food for the last hundred years or so, salt has been the best-known food preservative for meat, for many thousands of years. A ancient salt-works operation has been discovered at the Poiana Slatinei archaeological site next to a salt spring in Lunca, Neamț County, Romania. Evidence indicates that Neolithic people of the Precucuteni Culture were boiling the salt-laden spring water through the process of briquetage to extract the salt as far back as 6050 BC; the salt extracted from this operation may have had a direct correlation to the rapid growth of this society's population soon after its initial production began. The harvest of salt from the surface of Xiechi Lake near Yuncheng in Shanxi, dates back to at least 6000 BC, making it one of the oldest verifiable saltworks.
There is more salt in animal tissues, such as meat and milk, than in plant tissues. Nomads who subsist on their flocks and herds do not eat salt with their food, but agriculturalists, feeding on cereals and vegetable matter, need to supplement their diet with salt. With the spread of civilization, salt became one of the world's main trading commodities, it was of high value to the ancient Hebrews, the Greeks, the Romans, the Byzantines, the Hittites and other peoples of antiquity. In the Middle East, salt was used to ceremonially seal an agreement, the ancient Hebrews made a "covenant of salt" with God and sprinkled salt on their offerings to show their trust in him. An ancient practice in time of war was salting the earth: scattering salt around in a defeated city to prevent plant growth; the Bible tells the story of King Abimelech, ordered by God to do this at Shechem, various texts claim that the Roman general Scipio Aemilianus Africanus ploughed over and sowed the city of Carthage with salt after it was defeated in the Third Punic War.
Salt may have been used for barter in connection with the obsidian trade in Anatolia in the Neolithic Era. Salt was included among funeral offerings found in ancient Egyptian tombs from the third millennium BC, as were salted birds, salt fish. From about 2800 BC, the Egyptians began exporting salt fish to the Phoenicians in return for Lebanon cedar and the dye Tyrian purple. Herodotus described salt trading routes across Libya back in the 5th century BC. In the early years of the Roman Empire, roads were built for the transportation of salt from the salt imported at Ostia to the capital. In Africa, salt was used as currency south of the Sahara, slabs of rock salt were used as coins in Abyssinia. Moorish merchants in the 6th century traded salt for weight for weight; the Tuareg have traditionally maintained routes across the Sahara for the transportation of salt by Azalai. The caravans
In general use, herbs are plants with savory or aromatic properties that are used for flavoring and garnishing food, medicinal purposes, or for fragrances. Culinary use distinguishes herbs from spices. Herbs refers to the leafy green or flowering parts of a plant, while spices are dried and produced from other parts of the plant, including seeds, bark and fruits. Herbs have a variety of uses including culinary, in some cases, spiritual. General usage of the term "herb" differs between medicinal herbs; the word "herb" is pronounced in Commonwealth English, but is common among North American English speakers and those from other regions where h-dropping occurs. In botany, the word "herb" is used as a synonym for "herbaceous plant". In botany, the term herb refers to a herbaceous plant, defined as a small, seed-bearing plant without a woody stem in which all aerial parts die back to the ground at the end of each growing season; the term refers to perennials, although herbaceous plants can be annuals, or biennials.
This term is in contrast to trees which possess a woody stem. Shrubs and trees are defined in terms of size, where shrubs are less than 10 meters tall, trees may grow over 10 meters; the word herbaceous is derived from Latin herbāceus meaning "grassy", from herba "grass, herb". Another sense of the term herb can refer to a much larger range of plants, with culinary, therapeutic or other uses. For example, some of the most described herbs such as Sage and Lavender would be excluded from the botanical definition of a herb as they do not die down each year, they possess woody stems. In the wider sense, herbs may be herbaceous perennials but trees, shrubs, lianas, mosses, algae and fungi. Herbalism can utilize not just stems and leaves but fruit, roots and gums; therefore one suggested definition of a herb is a plant, of use to humans, although this definition is problematic since it could cover a great many plants that are not described as herbs. Ancient Greek philosopher Theophrastus divided the plant world into trees and herbs.
Herbs came to be considered in namely pot herbs, sweet herbs and salad herbs. During the seventeenth century as selective breeding changed the plants size and flavor away from the wild plant, pot herbs began to be referred to as vegetables as they were no longer considered only suitable for the pot. Culinary herbs are distinguished from vegetables in that, like spices, they are used in small amounts and provide flavor rather than substance to food. Herbs can be perennials such as thyme, sage or lavender, biennials such as parsley, or annuals like basil. Perennial herbs can be shrubs such as rosemary, Rosmarinus officinalis, or trees such as bay laurel, Laurus nobilis – this contrasts with botanical herbs, which by definition cannot be woody plants; some plants are used as both herbs and spices, such as dill weed and dill seed or coriander leaves and seeds. There are some herbs, such as those in the mint family, that are used for both culinary and medicinal purposes. Emperor Charlemagne compiled a list of 74 different herbs.
The connection between herbs and health is important in the European Middle Ages--The Forme of Cury promotes extensive use of herbs, including in salads, claims in its preface "the assent and advisement of the masters of physic and philosophy in the King's Court". Some herbs can be infused in boiling water to make herbal teas; the dried leaves, flowers or seeds are used, or fresh herbs are used. Herbal teas tend to made from aromatic herbs, may not contain tannins or caffeine, are not mixed with milk. Common examples include mint tea. Herbal teas are used as a source of relaxation or can be associated with rituals. Herbs were used in prehistoric medicine; as far back as 5000 BCE, evidence that Sumerians used herbs in medicine was inscribed on cuneiform. In 162 CE, the physician Galen was known for concocting complicated herbal remedies that contained up to 100 ingredients; some plants contain phytochemicals. There may be some effects when consumed in the small levels that typify culinary "spicing", some herbs are toxic in larger quantities.
For instance, some types of herbal extract, such as the extract of St. John's-wort or of kava can be used for medical purposes to relieve depression and stress. However, large amounts of these herbs may lead to toxic overload that may involve complications, some of a serious nature, should be used with caution. Complications can arise when being taken with some prescription medicines. Herbs have long been used as the basis of traditional Chinese herbal medicine, with usage dating as far back as the first century CE and far before. In India, the Ayurveda medicinal system is based on herbs. Medicinal use of herbs in Western cultures has its roots in the Hippocratic elemental healing system, based on a quaternary elemental healing metaphor. Famous herbalist of the Western tradition include Avicenna, Paracelsus and the botanically inclined Eclectic physicians of 19th
Salt in Chinese history
Salt, salt production, salt taxes played key roles in Chinese history, economic development, relations between state and society. The lure of salt profits led to new ways to organize capital. Debate over government salt policies brought forth conflicting attitudes toward the nature of government, private wealth, the relation between the rich and the poor, while the administration of these salt policies was a practical test of a government's competence; because salt is a necessity of life, the tax on it had a broad base and could be set at a low rate and still be one of the most important sources of government revenue. In early times, governments gathered salt revenues by managing production and sales directly. After innovations in the mid-8th century, imperial bureaucracies reaped these revenues safely and indirectly by selling salt rights to merchants who sold the salt in retail markets. Private salt trafficking persisted because monopoly salt was more expensive and of lower quality, while local bandits and rebel leaders thrived on salt smuggling.
Over time, this basic system of bureaucratic oversight and private management yielded revenue second only to the land tax, with considerable regional variation and periodic reworking, remained in place until the mid-20th century. Salt played a role in Chinese society and culture. Salt is one of the "seven necessities of life" mentioned in proverbs and "salty" is one of the "five flavors" which form the cosmological basis of Chinese cuisine. Song Yingxing, author of the 17th century treatise, The Exploitation of the Works of Nature explained the essential role of salt: as there are five phenomena in weather, so are there in the world five tastes… A man would not be unwell if he abstained for an entire year from either the sweet or sour or bitter or hot. In earliest times and island salterns used earthen and iron boiling pans to reduce sea water to salt. By the 3rd century BCE, workers filtered sea water through flat beds of ashes or sand into pits to produce a brine which could be boiled or evaporated by the sun.
By the Ming dynasty, salterns in the salt marshes of northern Jiangsu and the eastern seaboard at Changlu, Bohai Bay, near present-day Tianjin, became the largest salt producers and by the late 19th century supplied some 80% of China's salt. Over the course of the 20th century, industrial evaporators replaced these coastal salterns. Well salt: produced in Sichuan, most famously at Zigong, but to some extent in Yunnan. Deep borehole drilling technology tapped subterranean salt pools, sometimes to the depth of half a mile, which produced the natural gas used to boil it; however by the end of the 19th century, Sichuan produced only 8% of China's salt. Lake salt: produced from salt water lakes in Western China and Central Asia using the same evaporative techniques as for sea water. Earth salt: found in sand from the dried beds of ancient inland seas in Western areas and extracted by rinsing it to produce brine. Rock salt: found in caves in Shaanxi and Gansu. Song Yingxing, the Ming dynasty technology writer, explains that in the prefectures where there is no sea salt or salt wells, people find “rocky caves which produce salt by themselves, its color being like that of red earth.
People can obtain it by scraping it off without refining it.” As in other ancient centers of civilization, when agriculture replaced hunting, who ate little meat, needed salt for themselves and for their draft animals. More than a dozen sites on the southwest coast of the Bohai Bay show that the Dawenkou culture was producing salt from underground brine more than 6,000 years ago during the Neolithic. In the same region, the late Shang dynasty produced salt on a large scale and moved it inland in "helmet shaped-vessels"; these pottery jars may have served as "standard units of measurement in the trade and distribution of salt". Oracle bones mention "petty officers for salt", suggesting that the Shang had officials who oversaw salt production and provisioning; the earliest surviving record of salt production in what is now China is a text from 800 BCE which reports that the much earlier Xia dynasty reduced sea water for salt. There are reliable reports of the use of iron salt pans in the 5th century BCE.
Early states located their capital cities near ready sources of salt, a consideration which affected locations in times. In the 3rd century BCE, Li Bing, an official of the expansionist and innovative Qin dynasty, in addition to organizing the Sichuan basin water control system at Dujiangyan, discovered that the salt pools, used for many centuries were fed from deep under the ground, the remnants of an ancient inland sea, he ordered first that the pools be made deeper that wells be dug, that narrower and more efficient shafts be sunk. By the end of the 2nd century CE, workers had devised a system of leather valves and bamboo pipes which drew up both brine and natural gas, which they burned to boil the brine. Before the Qin's wars of unification in 221 BCE, salt was produced and traded and presented as tribute to the courts of the regional states; the Guanzi, a Han dynasty comp
Curing (food preservation)
Curing is any of various food preservation and flavoring processes of foods such as meat and vegetables, by the addition of salt with the aim of drawing moisture out of the food by the process of osmosis. Because curing increases the solute concentration in the food and hence decreases its water potential, the food becomes inhospitable for the microbe growth that causes food spoilage. Curing can be traced back to antiquity, was the primary way of preserving meat and fish until the late-19th century. Dehydration was the earliest form of food curing. Many curing processes involve smoking, cooking, or the addition of combinations of sugar, nitrite. Meat preservation in general comprises the set of all treatment processes for preserving the properties, taste and color of raw cooked, or cooked meats while keeping them edible and safe to consume. Curing has been the dominant method of meat preservation for thousands of years, although modern developments like refrigeration and synthetic preservatives have begun to complement and supplant it.
While meat-preservation processes like curing were developed in order to prevent disease and to increase food security, the advent of modern preservation methods mean that in most developed countries today curing is instead practised for its cultural value and desirable impact on the texture and taste of food. For lesser-developed countries, curing remains a key process in the production and availability of meat; some traditional cured meat are cured with salt alone. Today, potassium nitrate and sodium nitrite are the most common agents in curing meat, because they bond to the myoglobin and act as a substitute for the oxygen, thus turning myoglobin red. More recent evidence shows that these chemicals inhibit the growth of the bacteria that cause the disease botulism; the combination of table salt with nitrates or nitrites, called curing salt, is dyed pink to distinguish it from table salt. Neither table salt, nor any of the nitrites or nitrates used in curing is pink. Untreated meat decomposes if it is not preserved, at a speed that depends on several factors, including ambient humidity and the presence of pathogens.
Most meats cannot be kept at room temperature in excess of a few days without spoiling. If kept in excess of this time, meat begins to change color and exude a foul odor, indicating the decomposition of the food. Ingestion of such spoiled meat can cause serious food poisonings, like botulism. Salt-curing processes have been developed since antiquity in order to ensure food safety without relying on artificial anti-bacterial agents. While the short shelf life of fresh meat does not pose a significant problem when access to it is easy and supply is abundant, in times of scarcity and famine, or when the meat must be carried over long voyages, it spoils quickly. In such circumstances the usefulness of preserving foods containing nutritional value for transport and storage is obvious. Curing can extend the life of meat before it spoils, by making it inhospitable to the growth of spoilage microbes. A survival technique since prehistory, the preservation of meat has become, over the centuries, a topic of political and social importance worldwide.
Food curing dates back both in the form of smoked meat and salt-cured meat. Several sources describe the salting of meat in the ancient Mediterranean world. Diodore of Sicily in his Bibliotheca historica wrote that the Cosséens in the mountains of Persia salted the flesh of carnivorous animals. Strabo indicates that people at Borsippa were salting them to eat; the ancient Greeks prepared tarichos, meat and fish conserved by salt or other means. The Romans called this dish salsamentum – which term included salted fat, the sauces and spices used for its preparation. Evidence of ancient sausage production exists; the Roman gourmet Apicius speaks of a sausage-making technique involving œnogaros. Preserved meats were furthermore a part of religious traditions: resulting meat for offerings to the gods was salted before being given to priests, after which it could be picked up again by the offerer, or sold in the butcher's. A trade in salt meat occurred across ancient Europe. In Polybius's time, the Gauls exported salt pork each year to Rome in large quantities, where it was sold in different cuts: rear cuts, middle cuts and sausages.
This meat, after having been salted with the greatest care, was sometime smoked. These goods had to have been important, since they fed part of the Roman people and the armies; the Belgae were celebrated above all for the care. Their herds of sheep and pigs were so many, they could provide skins and salt meat not only for Rome, but for most of Italy; the Ceretani of Spain drew a large export income from their hams, which were so succulent, they were in no way inferior to those of Cantabria. These tarichos of pig would become sought, to the point that the ancients considered this meat the most nourishing of all and the easiest to digest. In Ethiopia, according to Pliny, in Libya according to Saint Jerome, the Acridophages salted and smoked the crickets which arrived at their settlements in the spring in great swarms and which constituted, it was said, their sole food; the smoking of meat was a traditional practice in No
Salt in the American Civil War
Salt was a crucial resource during the American Civil War. Salt not only preserved food in the days before refrigeration, but was vital in the curing of leather. Union general William Tecumseh Sherman once said that "salt is eminently contraband", as an army that has salt can adequately feed its men; the most important saltworks for the Confederacy were at Virginia. In late 1864, the Union army twice advanced to capture the saltworks, as it was the last prominent source of salt for the eastern Confederate states; the October 1864 Battle of Saltville I saw the Confederate able to repulse the charge, but the next December in the Battle of Saltville II Union forces under George Stoneman managed to destroy the vital saltworks. Two months the salt works were back to work for the Confederacy, although the destroyed railroad system around the area hampered its distribution. In Georgia, the price of salt depended on one's family circumstances. Heads of families could purchase a half-bushel of salt for $2.50.
If a widow had a son in the Confederate army, the price was only $1.00. But if the widow's husband served his nation, the price was free. Local court clerks sent the salt requests to the state government, which in turn allotted the salt to the counties as requested. Florida's greatest contribution to the Confederate war effort was in producing salt. With a total investment of $10 million, Floridian salt plants worked 24 hours a day boiling salt from sea water in the area between Saint Andrews Bay and St. Marks, Florida. Union forces came ashore just to destroy the boilers. Confederate law made those involved in salt-making immune to being drafted, making it a popular profession in war-time Florida. One way Southern families acquired salt was to boil the dirt in areas where they had cured meats, they would dig it out, strain it. Avery Island, off the Louisiana coast, gave the Confederacy a huge supply of rock salt until the Union captured it. However, Confederates never realized that similar structures to the Avery Island salt dome were all along the Louisiana and Texas coasts of the Gulf of Mexico, could have provided a more acquired source of salt
Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of vesicular rough textured volcanic glass, which may or may not contain crystals. It is light colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser. Pumice is created when super-heated pressurized rock is violently ejected from a volcano; the unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases that are dissolved in the lava, causing the gases to exsolve; the simultaneous cooling and depressurization freezes the bubbles in a matrix. Eruptions under water are cooled and the large volume of pumice created can be a shipping hazard for cargo ships. Pumice is composed of microvesicular glass pyroclastic with thin, translucent bubble walls of extrusive igneous rock, it is but not of silicic or felsic to intermediate in composition, but basaltic and other compositions are known.
Pumice is pale in color, ranging from white, blue or grey, to green-brown or black. It forms when volcanic gases exsolving from viscous magma form bubbles that remain within the viscous magma as it cools to glass. Pumice is a common product of explosive eruptions and forms zones in upper parts of silicic lavas. Pumice has a porosity of 64–85% by volume and it floats on water for years, until it is waterlogged and sinks. Scoria differs from pumice in being denser. With larger vesicles and thicker vesicle walls, scoria sinks rapidly; the difference is the result of the lower viscosity of the magma. When larger amounts of gas are present, the result is a finer-grained variety of pumice known as pumicite. Pumice is considered a volcanic glass. Pumice varies in density according to the thickness of the solid material between the bubbles. After the explosion of Krakatoa, rafts of pumice drifted through the Indian Ocean for up to 20 years, with tree trunks floating among them. In fact, pumice rafts support several marine species.
In 1979, 1984 and 2006, underwater volcanic eruptions near Tonga created large pumice rafts, some as large as 30 kilometers that floated hundreds of kilometres to Fiji. There are two main forms of vesicles. Most pumice contains tubular microvesicles; the elongation of the microvesicles occurs due to ductile elongation in the volcanic conduit or, in the case of pumiceous lavas, during flow. The other form of vesicles are subspherical to spherical and result from high vapor pressure during eruption. Pumice is igneous rock with a foamy appearance; the name is derived from the Latin word "pumex" which means "foam" and through history has been given many names because its formation was unclear. The old English term was “Spuma Maris”, meaning froth of the sea, because it was a frothy material thought to be hardened sea foam, it was known as “écume de mer” in French and “Meerschaum” in German for the same reason. Around 80 B. C. in Greek civilization it was called “lapis spongiae” for its vesicular properties.
Many Greek scholars decided there were different sources of pumice, one of, in the sea coral category. Pumice can be found all around the globe deriving from continental volcanic occurrence and submarine volcanic occurrence. Floating stones can be distributed by ocean currents; as described earlier pumice is produced by the eruption of explosive volcanoes under certain conditions, natural sources occur in volcanically active regions. Pumice is transported from these regions. In 2011, Italy and Turkey led pumice mining production at 3 million tonnes respectively. Total world pumice production in 2011 was estimated at 17 million tonnes. There are large reserves of pumice in Asian countries including Afghanistan, Japan, Syria and eastern Russia. Considerable amounts of pumice can be found at the Kamchatka Peninsula on the eastern flank of Russia; this area contains 19 active volcanoes and it lies in close proximity with the Pacific volcanic belt. Asia is the site of the second-most dangerous volcanic eruption in the 20th century, Mount Pinatubo, which erupted on June 12, 1991 in the Philippines.
Ash and pumice lapilli were distributed over a mile around the volcano. These ejections filled trenches. So much magma was displaced from the vent than the volcano became a depression on the surface of the Earth. Another well-known volcano that produces pumice is Krakatoa. An eruption in 1883 ejected so much pumice that kilometers of sea were covered in floating pumice and in some areas rose 1.5 meters above sea level. Europe is the largest producer of pumice with deposits in Italy, Greece and Iceland. Italy is the largest producer of pumice because of its numerous eruptive volcanoes. On the Aeolian Islands of Italy, the island of Lipari is made up of volcanic rock, including pumice. Large amounts of igneous rock on Lipari are due to the numerous extended periods of volcanic activity from the Upper Pleistocene/Tyrrhenian to the Post-Pleistocene periods. Pumice can be found all across North America including on the Caribbean Islands. In the United States, pumice is mined in Nevada, Idaho, California, New