The Geology
Zinc is never found as the free metal. It makes up about .0075% of the Earth's crust, making it the 24th most abundant element. Soil contains 5–770 ppm of zinc with an average of 64 ppm and it is the fourth most common metal in use, trailing only iron, aluminum, and copper with an annual production of about 13 million tons.
Zinc ores are recovered by many mining techniques, ranging from open-pit mining (mainly in the case of oxidized ore bodies, which are located closer to Earth's surface) to the normal underground methods (used for the more deeply located sulfide ores).
Zinc resources total about 1.9 billion tones worldwide. The three top producing countries of zinc in the world are China, Peru and Australia followed by India, USA and Canada. At the current rate of consumption, one source has estimated these reserves could be depleted sometime between 2027 and 2055. About 346 million tons have been extracted throughout history to 2002, and one estimate found that about 109 million tons of that remains in use.
It is commonly found in association with other mineral deposits such as copper and in various ores, and is most commonly used as an anti-corrosion agent. The main zinc ore mineral is called sphalerite, which is a zinc sulphide. Sphalerite is also known as zinc blende and contains 67% zinc when pure. The main deposit type that is mined for zinc is silver-lead-zinc strataform and strata-bound deposits.
Physical Properties
Zinc is a bluish-white, lustrous, metal, though most common commercial grades of the metal have a dull finish. Zinc is a Chemical element with symbol Zn and atomic number 30. It is the first element in Group 12 element Periodic table. In some respects zinc is chemically similar to Magnesium. Zinc is the 24th most abundant elements in Earth's crust and has five stable isotopes. The Geology
Zinc is never found as the free metal. It makes up about .0075% of the Earth's crust, making it the 24th most abundant element. Soil contains 5–770 ppm of zinc with an average of 64 ppm and it is the fourth most common metal in use, trailing only iron, aluminum, and copper with an annual production of about 13 million tons.
Zinc ores are recovered by many mining techniques, ranging from open-pit mining (mainly in the case of oxidized ore bodies, which are located closer to Earth's surface) to the normal underground methods (used for the more deeply located sulfide ores).
Zinc resources total about 1.9 billion tones worldwide. The three top producing countries of zinc in the world are China, Peru and Australia followed by India, USA and Canada. At the current rate of consumption, one source has estimated these reserves could be depleted sometime between 2027 and 2055. About 346 million tons have been extracted throughout history to 2002, and one estimate found that about 109 million tons of that remains in use.
It is commonly found in association with other mineral deposits such as copper and in various ores, and is most commonly used as an anti-corrosion agent. The main zinc ore mineral is called sphalerite, which is a zinc sulphide. Sphalerite is also known as zinc blende and contains 67% zinc when pure. The main deposit type that is mined for zinc is silver-lead-zinc strataform and strata-bound deposits.
A bar of zinc generates a characteristic sound when bent, similar to Tin cry.
History of Zinc
Zinc is also known as "white bronze" making it sound like a more expensive product. The name "zinc" only came into general use in the 17th century following rediscovery of the material.
Centuries before zinc was discovered in the metallic form, its ores were used for making brass. It was Marco Polo (1254-1324) from Venice who reported the production of zinc oxide in Persia. At this time the Persians used a solution of zinc vitriol to treat eye inflammations. Zinc sulphate is used in medicine as an adstringent and antiseptic even today.
It has derived its name from the German word “Zinke", which means 'tooth-like' or 'pointed'. It is believed that Paracelsus, a noted German alchemist of the medieval period, gave this name. This element is also called by various other names like Indian tin, calamine, etc. Zinc was found to be especially suitable for alloys with other metals and was therefore first of all employed to make coins. Although zinc ores have been in use since the Bronze Age, it was not until very much later that zinc was discovered to be an element, i.e. a substance that cannot be broken down further. Zinc was generally imported from India until the end of the 18th century and was considered to be very costly.
Metallic zinc was produced in India ca. 1200 AD, and the process is described as the production of a new metal similar to tin. It involved heating the zinc ore indirectly with charcoal in a covered crucible. This produced zinc vapour, which was cooled by the ambient air in a condensation recipient underneath the crucible. This is how metallic zinc was formed.
By 1374 zinc had been recognized by the Hindus as a new metal, the eighth known in that day and age, and zinc production and trading was already underway on a limited scale...
Using Zinc as Tombstones
White Bronze monuments were made for only 40 years. Unlike traditional gravestones and markers, there were not any stores where you could go to see or purchase a white bronze monument. These were only sold through company catalogs and in person by a sales agent. If you wanted to see a white bronze marker, you would have to go to a cemetery. You could choose the designs for the attached panels.
The monuments were made up and then the names and other personalization were added when sold. They were easier to construct than traditional stone monuments, as well as, cheaper to produce and ship. Sales hit their peak in the 1880s. Some people however, thought the monuments cheap imitations and banned them. By WWI, production was shut down as all zinc was needed for the war effort.
To construct the monument a mold was constructed just like for granite or marble monuments. After the mold was finished, the zinc was heated beyond its melting point to ensure a better fuse then traditional soldering. The monument was then sandblasted and chemically oxidized to resemble granite and receive its bluish cast. When exposed to the carbon dioxide in the atmosphere, zinc naturally covers itself in a layer of zinc carbonate. This prevents further reaction with air and water. Strong acids, or even acid rain, however will still trigger a chemical reaction.
One problem that cemeteries has is weathering of stones or the breakdown of rock in situ, that is without moving, and should not to be confused with erosion. Weathering varies by location based on a host of variables, but a study in Yorkshire, England found that the average marble stone became difficult to read after 70-80 years while igneous rocks, like granite, lasted up to 100-150 years in comparison.
Traditional stones are made of granite, limestone, or marble. Marble tends to be a very soft stone and weathers quickly. Granite tends to take a while longer, but still fades over time. Limestone is affected by acid rain but will last rather a long time.
Although white bronze monuments weathered well, they have one flaw know as creep or bend. This occurs when the weight of the top of the monument bears down onto the base and it begins to bow or bulge-very slowly, over the years. This creeping action may also cause tiny cracks on some of the monuments. The only way to rectify this is to place a stainless steel armature inside the base to help support the upper weight. Obviously, smaller markers do not exhibit this problem. Proper seating/mounting on concrete bases was important to reduce creep & corrosion from prolonged contact with the soils.
In an attempt to boost sales, the Monumental Bronze Company changed the "finish" on the metal base so it would resemble stone. The sandblasting roughened the surface and speed up the natural formation of protective oxide coating. Many pre 1879 monuments are smooth with a grayish colour while the post 1879 monuments have rough surface and are more bluish-silver in colour.
To Log this EarthCache:
Rules:
1. Parking is available
2. Please do not take a photo of any monument that identifies a family name. You may take pictures of the tombstones provided that the names are obscured. Please take care when walking around as the ground is uneven in places. Restoration is in progress in the cemetery.
Monument is at:
1. Do you see any evidence of “creeping” on this one? Is the monument on a base yes or no?
2. Compare the weathering of the white bronze monument to those around it. In terms of readability and resistance to lichens and discolorations, which markers are holding up the best?
3. How long do you think that these monuments might last in comparison to other monuments in the area?
4. You will need the age of the person: year, months and days?
5. Is the zinc monument solid or hollow? Try tapping lightly.
Send me your answers to my profile. Do not post your answers on in your log.