Blog

Archive for the ‘Miscellaneous’ Category

The Science of Gold

Gold is one of the heavy metal elements and comparatively rare. Precious metals like gold, platinum and silver are created when neuron stars crash together. These small but incredibly dense stars contain the huge amount of energy needed to create the metals when they collide. This precious metals are then thrown out into the universe where they combine with other stardust into planets and comets. When our planet was being formed, most of its gold sank into the earth’s core. Scientists estimate there’s enough gold in our planet’s core to cover the whole surface to a depth of 1.5 feet – if we could only reach it.

Gold on our planet

The gold we mine, use and refine in our society comes from surface deposits of gold. These originate from meteorites that crashed into the earth and left the gold behind many eons ago, before all of human history. For example, some of the largest gold deposits in South Africa are estimated to be three billion years old.

Gold is found on every continent although about 40% of all gold was mined at Witwatersrand, in South Africa. Some gold is found in rock formations such as quartz and iron pyrite, and in natural alloys with silver and copper. This is called gold ore. Small particles of gold can also be embedded in rock with other minerals such as pyrite or ‘fool’s gold’ to form a lode deposit.

Gold ore from California

Gold ore

Flakes and nuggets of gold can be found in rivers and streams. These are made up of particles of gold eroded away from rocks. The particles travel down into the water and eventually collect into larger pieces of gold. These are called ‘placer’ deposits from the Spanish word for a sandbank.

Fascinatingly, research has shown that bacteria may also be responsible for creating nuggets of pure gold. Some bacteria have a genetic resistance to heavy metal toxicity and can dissolve gold into nanoparticles. These then travel through sediment and accumulate into nuggets. In fact the largest nuggets ever discovered were found underground in mines. The Canaã nugget is the largest gold nugget currently in existence. It was found in the Serra Pelada mine in Brazil and contains 115.37 lb of gold.

Humans have been mining for gold since the earliest civilisations yet all the gold ever mined in the world could be contained in three Olympic sized swimming pools. It’s thought that there is approximately only another 20 years’ worth of gold left that can be easily mined.

Other sources of gold

Our planet’s oceans contain a huge quantity of gold, approximately 10 – 20 million tons. However the gold is dispersed throughout the waters in tiny amounts of about 1 gram in 100,000 tons of seawater. Many have tried to invent schemes to extract the gold from water. Yet the gold in our oceans remains too difficult and expensive to obtain.

Our bodies also contain about 0.2 milligrams of gold with most of it flowing through our blood.

What are the qualities of gold?

Gold is very stable. This means it doesn’t rust or tarnish like other metals such as silver. Of all the different kinds of metals, gold is the only one that is both coloured and keeps its shine forever. You could bury gold for thousands of years and it would remain un-corroded and shining bright.

Gold is the least reactive of all the chemical elements. It is unaffected by most acids and chemical bases. As a result it is one of the few elements that can be found in its pure natural state. Miners in the nineteenth century knew that gold didn’t react to most other chemicals and used this to test the purity of their finds. They took nitric acid and dripped it onto the metal. If the gold didn’t dissolve or react this showed that it was pure. It is from this practice that we get the phrase ‘acid test’.

Nineteenth century gold miners

Gold can be dissolved with a solution called ‘aqua regia’ first discovered by the alchemists. This is a mixture of nitric and hydrochloride acid that together act as a powerful oxidizer to break the gold down.

Gold is very malleable and soft. It can be beaten out into super-thin sheets, for example a piece of gold about the size of a grain of rice can be beaten flat to cover one square metre. Gold can even be manufactured thin enough to make it semi-transparent.

All of these properties of gold are related to the way the atoms in the gold bond to one another. The strong bonds between the gold atoms stop gold from reacting with other elements and tarnishing. Gold’s molecular structure is held together tightly which creates its malleability and high conductivity. Gold also has very dense and mobile electrons which is why the metal shines when the light bounces off of it.

What is pure gold?

The carat system is commonly used to describe how pure gold is. 24 carat gold is considered to be unadulterated gold. 18 carat gold is 75 % gold or 18 parts gold with 6 parts formed of another metal. In actual practice it’s impossible for gold to be completely 100 % pure but the amount of acceptable impurity is very small at 0.01 %. The absolute purest known sample of gold was produced at the Perth mint in Australia and was confirmed to be 999.999 % pure gold.

Different carats of gold

The word carat comes from the Arabic name for the seed of the carob tree. In the days before standardised measurements, the carob seed was used to weigh gold because people believed the seeds all weighed the same – although this wasn’t actually true. One pure gold coin was considered to weigh the same as 24 carob seeds and so 24 carat gold was used as a measurement of 100 % gold.

Gold alloys

Gold can be melted and mixed with other metals or chemicals to form an alloy. This gives the alloy characteristics of both substances. Gold, for example can be combined with another metal to strengthen it and make an alloy that is tough enough for everyday use.

Ancient civilisations such as in Egypt and Greece knew how to make gold alloys. They mixed gold with other metals to create brightly coloured alloys for jewellery and decoration, such as iron and gold which combined to make a vivid burgundy red metal.

Today white gold and rose gold are common alloys. White gold is a combination of gold and white metal such as silver, palladium, platinum and nickel. A nickel and gold mix makes the alloy strong and hard whereas platinum and gold produces a heavy and durable alloy.

Rose gold is made from gold and copper. The more copper there is in the alloy, the brighter red it becomes. Rose gold was so popular in Russia during the nineteenth century that it became known as Russian gold.

Gold can be mixed with other metals and chemicals to produce alloys ranging in colour from black to blue, grey, green and purple.

The nature of gold means that it’s quite easy to separate it from an alloy. As gold is unreactive, a gold alloy can be heated with salt to make the other metals burn away or be absorbed to leave the pure gold behind.

Gold alloys

Synthetic gold

It is possible to create artificial gold. In 1924 a Japanese physicist produced gold from mercury by bombarding it with neutrons – but the gold was radioactive. Since then experiments have included using a particle accelerator to transform bismuth to gold, and irradiating platinum and mercury in a nuclear reactor.

The problem is that gold is produced by immense amounts of energy and heat from the fusion of dying stars. We could replicate some of those conditions using a supercollider but it would be too expensive and take too long to produce enough metal for it to be a feasible source of gold.

The reclamation of gold

There is an alternative source of gold to mining or artificial experiments. The reclamation of previously used gold is an increasing source of the metal. As well as for jewellery, gold is often used in the electronics industry. The properties of gold such as its high conductivity and lack of tarnish mean it is used in circuit boards and wiring. As a result obsolete electronic devices such as computers and mobile phones are now a substantial source of recoverable gold. For example in 2015 Apple obtained over 2000 lbs of gold from broken iPhones.

It is now both profitable and more environmentally friendly to recycle the gold that has already been in use, rather than extract fresh gold from mining into the earth.

Gold recycling

References

More reading

May 15th, 2018 No Comments » Miscellaneous |

The history of alchemy and the search for gold

What is alchemy? Alchemy is most well-known for its attempts to change common metals into silver and gold. Yet is an ancient discipline originally studied in Egypt and the Greek Hellenistic empire, China and India. 

The origins of alchemy

Alchemy came to Western Europe from the Islamic kingdoms in the twelfth century. Arabic alchemical books were initially translated by the Christian church. Its ideas of transmutation became increasingly popular. Interest in alchemical gold peaked between the sixteenth and eighteenth centuries at a time of numerous famines and wars and a great need for money to fund them. Yet alchemy was more than just a fantastical get-rich-quick scheme. It combined ideas from early science and medicine with religious and metaphysical beliefs.

Geberi philosophi ac alchimistae maximi de alchimia libri tres, 1531

Alchemists wanted to change one thing into another. In order to do this, practitioners first had to think about what their substances were made up of and how they could alter them. In the days before modern science, alchemy was one way to think about the world and try to understand how it worked. By the late sixteenth century alchemy was regarded as a serious scientific and philosophical pursuit, despite its controversial nature. Leading scientific thinkers of the day such as Robert Boyle and Isaac Newton studied alchemy. Newton wrote more than a million words about it.

Theories of alchemy

There was no schools or guilds of alchemists with authorised teachings. This meant that there were many different theories and ideas about how alchemy worked.

Alchemists believed that everything was made up of the four elements of earth, air, fire and water. This was originally a Greek idea, from the philosopher Aristotle, who also believed that the universe was divided into two parts – heaven and earth.  What happened in heaven was reflected on the earth below. Alchemists thought the planets were connected to different metals on earth, for example gold was with linked with the sun and its associated properties.

This image shows the symbols for metals growing in the bowels of this alchemical man. From Becher, Johann Joachim. Physica subterraena. 1738.

Most people believed that metals were seeded deep into the earth by God when he created the world. Miners noticed that metal ores ran through rocks in veins that looked like plant roots, growing and spreading. Alchemists took this idea a step further. They believed that common metals like iron and lead could develop and mature into silver and then gold as the most perfect of all metals. Alchemists thought they could recreate this process of growth using the Philosopher’s Stone to turn common metals into gold.

The Philosopher’s Stone

Alchemists believed the Philosopher’s Stone had the power of transmutation and could be used to change metal into gold. They called this the ‘Great Work’ or ‘Magnum Opus’. Some alchemists thought the Philosopher’s Stone could also be an elixir or medicine that could extend their life and heal all diseases. They called this ‘potable’ or drinkable gold. Others saw the Philosopher’s Stone as a way to seek enlightenment and a higher spirituality. All they needed to do was find the right alchemical recipe to create it.

Alchemical ingredients

Alchemists used a wide range of materials in their quest for alchemical gold. Books and manuscripts list common ingredients such as metals, minerals like saltpetre and strong acids to dissolve substances so they could be added to the mix. Organic matter might include blood, hair and urine.

Other ingredients are more puzzling. Alchemical recipes often list ‘philosophical’ sulphur and mercury. These were not simply chemicals but somehow embodied certain properties that also needed to be combined to create the Philosopher’s Stone. For example, philosophical mercury was considered to contain female, silver and lunar principles. Alchemists sought to combine both the physical and metaphysical properties in their ingredients.

Common ingredients used in alchemy

Alchemical processes 

Once the alchemist had the right ingredients, the next step was to mix them up in the correct combination and then apply several different types of alchemical processes to them. These processes combined alchemical ideas with chemical operations. For example, the first process often involved calcination, which is when material is heated until it’s reduced to ashes. This also reflected the alchemical idea that matter had to be broken down into a basic, primal mass before reforming it into a higher state.

Alchemists used furnaces to control the amount of heat applied to their mixtures and carefully designed vessels and flasks to distil their ingredients by repeatedly boiling and condensing them.

Alchemical equipment

Whilst alchemists couldn’t agree on exactly what processes were involved, most thought that their mixture had to go through several different colour changes as part of the recipe. The first stage produced black matter which then became white as the ingredients were purified.  The heat of furnace was increased to turn the substance red, showing that the alchemist had successfully created the Philosopher’s Stone.

Who practiced alchemy?

In popular culture, alchemists are often shown as wise old men with long beards, labouring away in a dark and smoky laboratory. In reality alchemy was practised by a wide range of people. Some devoted their lives to alchemy and sought rich patrons to fund them. Those who were successful might be rewarded with supplies and equipment. However, if they failed, alchemists could be taken to court or worse. Duke Friedrick of Württemburg (1557–1608) in Germany found it particularly amusing to hang alchemical fraudsters on a gold plated gallows.

David Teniers the younger (1610 – 1690). L'alchimiste

Many alchemists were priests and monks. They believed their alchemical work was done with the permission of God and their research revealed the truth of God’s creation. Some alchemists sought the Philosopher’s Stone in order to receive religious enlightenment.

Kings and rulers could see the economic advantage of creating alchemical gold. Some monarchs tried to control alchemy by making it illegal without a special license – granted by them. Others encouraged alchemists to come to their court where they could keep an eye on them, sometimes with unpredictable results. The alchemist Sendivogius’ experiments at the court of Rudolf II in Krakow allegedly set the place on fire causing the King to move to Warsaw, where it became the capitol of Poland.

Alchemists might also be merchants, aristocrats, scholars, doctors, craft-workers, soldiers and cooks. Female authors wrote a number of alchemical books and manuscripts. Noblewomen were patrons and employers of alchemists. Some women used alchemical practices as part of their housekeeping duties.

Knowledge of alchemy was not just limited to its practitioners. Alchemical books and texts became increasingly popular in the sixteenth and seventeenth centuries and so its ideas came to spread throughout literature, theatre and the arts. You can find alchemical themes and ideas in Shakespeare, Chaucer and Milton’s works as well as alchemical images in paintings and architecture.

Symbolism and secrecy

Alchemy was a secret art right from its ancient origins. Texts warned their readers not to share their knowledge because it was too dangerous for the ignorant. So when alchemy arrived in Western Europe, authors continued to write down their recipes using codes and complicated metaphors to disguise their ingredients and practices. This protected their secrets as only another alchemist would be able to understand their words.

As the technology to print text and illustrations improved, alchemical books began to include drawings to accompany their recipes. Alchemists used symbolic images to represent and conceal their ingredients and instructions. These pictures were often a strange mix of emblems from the natural world, mythology and Christianity. They sometimes used startling combinations of sex, death and violence to symbolise chemical processes such as joining ingredients together or the symbolic death of substances into a blackened mass. The final red stage of the Philosopher’s Stone was often shown as a fiery phoenix, resurrected from the dead and able to transform metals into gold.

Mylius, Johann Daniel. Tractatus III Seu Basilica Philosophica. 1618.

The legacy of alchemy

Alchemists continually tried different ingredients, combinations and chemical processes in their quest for alchemical gold. As a result they discovered considerable information about chemicals and other substances. An alchemist named Hennig Brand discovered a new element in his search for the Philosopher’s Stone in 1669. After experiments with the residues from boiled-down urine, Brand found a white substance that glowed in the dark and burnt brilliantly. He named it phosphorus mirabilis meaning miraculous bearer of light. It was the first element discovered since antiquity.

Alchemical knowledge was used in medicine – informing the first uses of chemotherapy – and many other trades such as glass-working, mining and metal-working. However as alchemical beliefs about the structure of matter were disapproved by the first modern chemists, alchemy ceased to be a serious scientific pursuit. However, it has continued to influence our culture in psychology, art, literature and cinema – most notably the Harry Potter films. Alchemy, it seems, continues to transmute and change to remain a part of our society.

Ripley alchemical scroll

References

  • Battistini, Matilde; translated by Rosanna M. Giammanco Frongia. 2007. Astrology, magic, and alchemy in art. J. Paul Getty Museum. Los Angeles.
  • Edson, Gary. 2012. Mysticism and alchemy through the ages : the quest for transformation. McFarland & Company. London.
  • Greenberg, Arthur. 2007. From alchemy to chemistry in picture and story. Wiley. New Jersey.
  • Linden, Stanton J. 2007. Mystical metal of gold : essays on alchemy and Renaissance culture. AMS Press. New York.
  • Newman, William Royall. 2006. Atoms and alchemy : chymistry and the experimental origins of the scientific revolution. University of Chicago Press. London.
  • Principe, Lawrence. 2013. The secrets of alchemy. University of Chicago Press. London.

Relevant links

Other articles you may be interested in

November 20th, 2017 No Comments » Miscellaneous |

British Gold Refinery featured on BBC1’s Rip-Off Britain program

BBC investigation discovers British Gold Refinery pay much lower rates than what is quoted on their web site.

  • Investigation discovers British Gold Refinery pay much lower rates than what is quoted on their web site.
  • Sample items sent for evaluation by the BBC are also under weighed and gold content was under quoted.

Series 3 of BBC1’s flagship consumer program, Rip-Off Britain commenced on Monday 3rd September and featured an in-depth investigation into the practices of the British Gold Refinery.

The programme featured a consumer, Lisa Tate, who after receiving an online quote of £523 for her unwanted watch and encouraged by the promises of ‘excllent rates’ and ‘1st class service’ decided to send the item to the company.

Once the British Gold Refinery received Lisa’s watch, she was understandably shocked to be told they would be offering her almost 60% less for the item, just £214.

She was further dismayed to discover that she would have to pay them £50 to have her watch returned.

Following her experience, when interviewed by Rip-Off Britain, Lisa said:

I wouldn’t sell my watch to British Gold Refinery even if they offered the full value of it. I would rather flush it down the toilet than give it to them.

The BBC also conducted their own investigation into the British Gold Refinery by sending items of gold for valuation. Three items were sent, all independently verified by a jeweller to confirm weight and purity. Using the online calculator provided by British Gold Refinery, the items were valued at over £900.

When British Gold Refinery received the items, they dropped their valuation to just £335.94, a reduction of almost two-thirds. On further investigation, the BBC discovered that the bracelet which had been certified as being 18ct gold and weighing 8g had been valued based on it being 16ct gold and weighing just 4g. In addition, a gold chain certified as being 14ct gold was only valued as 9ct gold.

It took the BBC multiple requests to get their gold returned and it took 5-days before they finally received their items back.

This is not the first time that the British Gold Refinery has received unfavourable attention. Back in January 2012, the ASA adjudicated over claims of misleading advertising.

Further reading:

The scam behind the gold buying comparison websites

September 6th, 2012 1 Comment » Miscellaneous |

Royal Mint release first UK kilo gold and silver coins

UK 1 kilo gold and silver coinsIn commemoration of the London 2012 Olympics, the Royal Mint have unveiled the UK’s first ever 1-kilo gold and silver coins.

At an eye-watering £100,000.00, the kilo gold coin is priced at around 3 times its intrinsic gold value. The silver version is priced at £3,000.00, nearly 4 times its silver value.

Designed by Sir Anthony Caro, the gold coin has an ultra low issue limit of just 60. The silver version is limited to 2,012 pieces and has been designed by Tom Phillips.

One could argue that the uniqueness and collectability of these coins justify the high price tag, however anyone purchasing for investment purposes should take note that the world’s largest gold coin, a 1 Million Dollar Canadian Maple Leaf sold for just it’s scrap value back in June 2010.

Interestingly, The Royal Mint produced a 1 kilo gold coin in 2011 to commemorate the Royal Wedding. Minted for the island of Alderney, this coins had a bargain-basement price of just £40,000.00!

Tesco don’t recognise 21ct gold

When we wrote our Tesco Gold Exchange review (back in November), we speculated what a customer would be paid for Asian 21ct gold jewellery.

Well, it appears our suspicion was correct. We’ve just had confirmation from a customer who sent their 21ct wedding jewellery to Tesco’s for valuation and were offered a sum based on their 18ct rates.

Based on today’s prices, a customer sending 21ct gold to Tesco would be paid just 65.2% of its true value.

That’s a very poor deal!

May 25th, 2011 No Comments » Miscellaneous |