Gold : The Gift of the Magi

Topical Science

GOLD

Issue No. 1, January 2017

The Gift of the Magi

Issue, Date

Gold is a precious metal and a chemical element; symbol Au

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It is a symbol of royalty, since royal crowns were often made of gold.

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Gold was mined in Egypt from ancient times and was used extensively in the 2 burial chamber of the young King Tutankhamun. It has been used in Feugiat:art as well as jewellery and in decorative in coinage. Until recent times, it was the Cras congue, sapien vitae vestibulum basis for our currency. adipiscing, erat lacus commodo lectus, in imperdiet massa risus vel tellus. Sed tincidunt cursus libero.

3 As a chemical element, gold has a number of unique features. Unlike most metals, it is extremely resistant to corrosion. It does not react with air or water and is inert to most acids. Even nitric acid, which readily reacts with copper and silver, has no effect on gold. This is the basis for the ‘acid test’ for gold. However, a mixture of nitric and hydrochloric acids known as ‘aqua regia’ will dissolve this noble metal.

Gold is extremely dense. It has a relative atomic mass of 197, less than that of lead, which is 207, yet the density of gold relative to water is 19.29, while the relative density of lead is only 11.34.

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To Topical Science

Issue No. 1, January 2017

The reason for the high relative density of gold lies in its crystal structure, i.e. the way in which the gold atoms are arranged in the solid material. Gold atoms are relatively small and in solid gold they are very closely packed. The density of a material is measured by its mass to volume ratio (D = M/V), so when we have a relatively large mass, contained in a relatively small volume, we have a high-density material.

Gold is extremely malleable, so that it can be beaten into very thin sheets of gold leaf. Its softness and malleability allow it to be easily worked into ornaments and jewellery. Pure gold is too soft to retain its shape and it is also rather expensive, so when used in jewellery it is usually alloyed with other metals, such as copper or silver, for practical reasons, as well as to reduce the cost. White gold, which can be made by alloying gold with palladium or platinum, has become popular in recent years.

Like copper and silver, gold is a very good conductor of heat and electricity, with the added advantage of being corrosion-resistant. Because of this, it is finding use in electronic components. However, about 50% of gold produced today is still used for jewellery, 40% is used for investments and only about 10% for industrial applications, including uses in certain types of glass and in dentistry as well as in electronics.

Gold is rather rare. At the end of 2009, it was estimated that all of the gold that had ever been mined amounted to about 165,000 metric tonnes. (one metric tonne = 1,000 kilograms). As gold is almost indestructible, most of it is recycled, so about 85% of this gold is still available today.

Because of its chemical inertness, most gold is found ‘native’, as the free element, and in times past, it could be found buried in soil as nuggets, or as gleaming grains of gold in stream sediments. There have been several ‘gold rush’ events in recorded history, sparked off by the accidental discovery of a gold nugget. Those in California and the Yukon are famous.

In Ireland, there was a mini gold rush in County Wicklow in the late eighteenth century. On 15th September 1795, a group of labourers were felling trees on the estate of Lord Carysfort, when one of them spotted a gold nugget among the soil clinging to the roots of a fallen tree. Word got around and soon hundreds of local people were panning for gold in nearby streams, or digging up the soil along their banks. Many succeeded in finding gold nuggets and there was a free-for-all for about a month. However, eventually the authorities sent in the military to disperse the crowds that had come to Wicklow to dig for gold. The following year, an Act of Parliament was passed, asserting the right of the King of England to claim the gold. Engineers from the nearby Avoca copper mines took over the business of prospecting.

However, it seems the peasantry had already found most of the available gold by then. No mother lode was ever discovered and eventually operations were discontinued.

Fast forward to the present century and shortly before Christmas 2011, an Irish company, Conroy Gold and Natural Resources, announced an update on its gold project at Clontibret, Co. Monaghan. The company’s major shareholder is Professor Richard Conroy, who set up the company in 1995. Exploration by the company revealed a potential gold trend from Co. Cavan at the southwestern end to Co. Armagh in the northeast. One of the main target areas is near Clontibret. The amount of gold resources at Clontibret is estimated at over 600,000 ounces of gold and if it were to be mined, the lifetime of the mine would be about eleven years.

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Topical Science

Issue No. 1, January 2017

The geology at Clontibret consists of sedimentary rocks, dating from the Ordovician period, between 400 and 500 million years ago.. The strata consist of shale or siltstone alternating with layers of sandstone rocks.

Earth movements in the past have given rise to three phases of folding. The earliest phase dates from the Caledonian age. It is represented by folds, cleavage and movement, on what is known as the Orlock Bridge Fault. The second phase is also from the Caledonian and is shown mainly by folds, while the third phase shows faults, which occurred between Caledonian and Carboniferous times, about 300 million years ago.

Over a century ago, the mineral stibnite was discovered at Tullybuck-Lisglassan near Clontibret and shafts were sunk to extract it. Stibnite is a mineral containing antimony, so it was called the Clontibret antimony mine. Gold was discovered there much later, when samples from the old workings were analysed in the 1950s. Drilling was carried out by Can Erin Mines in the 1950s, and by Munster Base Metals in the 1970s.

Both these companies discovered high grades of gold in narrow veins, but often with poor recovery. Even though a shaft of the old Clontibret mine passed directly through one gold bearing structure, the very fine grained gold mineralisation was not observed until the 1950s.

Conroy Gold and Natural Resources have been working on a study to calculate the costs of operating a goldmine at Clontibret. But another gold rush is unlikely!

Margaret Franklin is a retired chemistry lecturer. This article first appeared in her ‘Topical Science’ column in ‘The Westmeath Independent’ 3