What is Gold?
Gold is a precious metal. It is mined in South Africa, United States of America, Australia, Brazil, Russia and Canada.
Gold is malleable, ductile and so is used to hold gems in place.
Gold has a financial as well as an ornamental function – it can be purchased for investment in the shape of ingots, medals or coins. The price of gold is set many times a day in the Stock Exchanges around the world.
Gold is measured in ‘carats’ which indicate the amount of gold in the piece in proportion to other metals. For instance gold designated as 18 carat has 750 parts of gold to 250 parts of other metals. Pure gold is 24 carat. The hallmark indicates the cartage.
There are different types of gold: yellow gold, rose gold and white gold – which differ from each other in terms of the other metals used.
The history of Gold began in the Middle East in 2,500 B.C. in Mesopotamia.
Gold coins date back to the second millennium BC and were known to be used in Greece by the 7th Century BC.
At the end of the eighteenth century, the French revolution took place and this together with the industrial revolution of the nineteenth century brought an increase in wealth to Europe. Gold jewellery was considered an indispensable item for the emerging social classes. Gold earrings and brooches became popular. The first machine for the production of gold chains was made in France in 1782.
The first gold factories opened in Germany at the beginning of the 20th century.
Traditionally gold (yellow gold) wedding rings are worn on the fourth finger of the left hand – this dates back from a Roman belief that the fourth finger was directly related to the heart.
Gold is associated with the 50th wedding anniversary.
Caring for Gold
Gold can become scratched and so should be kept apart from other jewellery and abrasives should be avoided.
Chlorine should be avoided as it attacks the alloys in gold.
Gold on its own can be cleaned in an ultrasonic cleaner.
Wash in warm soapy water and clean with a soft brush. However care will mainly depend on what is required for any gem stone which has been set into the metal.
• Avoid contact with other jewellery
• Avoid chlorine
• Clean in warm soapy water
• Clean in ultrasonic cleaner
• Take care to use cleaning materials appropriate to any gem set in the gold.
Gold has a specific gravity of 19.30. The crystal structure is cubic.
What is Platinum?
Platinum is one of the three precious metals – the others being gold and silver. It is silvery grey, grey-white or white in colour.
It forms in igneous rock as ores – in which the platinum grains are too minute to be seen by the naked eye. It is mainly found in South Africa, Canada and Alaska.
It is the rarest of the metals, found in few places.
It is hypo-allergenic and so suitable for sensitive skin.
The Ancient Egyptians and Pre Incan civilisations are recorded as having found traces of Platinum and it then re emerged in the 1700s.
Platinum was first recognized as a chemical element in 1735 but had been used for thousands of years prior to that.
Platinum is now used in catalytic converters and in heart pacemakers amongst other industrial uses.
Caring for Platinum
Platinum will not fade or tarnish and will keep its colour. However it should be stored away from other jewellery as it can get scratched.
It can be washed in warm, soapy water and cleaned with a soft cloth or brush.
It should be polished professionally in order to get rid of scratches and to maintain a high shine.
- Store away from other jewellery
- Wash in warm soapy water
- Obtain professional polish from time to time
The specific gravity is 21.40 and it measures 4 on the Mohs hardness scale.
The crystal structure is Cubic.
Platinum does not tarnish when exposed to the atmosphere.
A temperature of 1,773 degrees centigrade is needed to melt platinum.
Platinum is used in catalytic converters and in heart pacemakers.
What is Silver?
What is Silver?
Silver is a precious metal. It is found as nuggets or grains. Most silver is a by-product of lead mining. Newly mined, it is metallic and has a bright, silver white colour, but the surface is soon tarnished by exposure to oxygen.
The metal is mainly found in South America, (especially Mexico) the USA, Australia and the former USSR.
Sterling silver is at least 92.5% silver.
It is known that the Ancient Greeks used Electrum – a gold and silver alloy, which was 25% silver.
Medieval silver was used in order to mount very colourful stones
Historically, there are references to pieces of silver which used vast quantities - such as the chair overlaid with silver used by Jean 11 of France, the father of Charles V.
Before banks were established, silver was melted down into coins as a way of safeguarding wealth.
Large quantities of silver were lost during the Civil War and during the Reformation years when Henry V111 dissolved the monasteries.
Silver was the only white precious metal in use until the mid 1800s when platinum was developed.
Silver is associated with the 25th wedding anniversary.
Caring for Silver
Silver is soft and malleable and so is easily dented or bent. Sterling silver tarnishes but care must be taken that the foams used to remove the tarnish, don’t also remove some of the silver. Use a soft cleaning cloth and warm sudsy water. Do not use toothpaste or any other abrasive substance to clean silver. Do not use ultrasonic cleaners.
• Take care not to bend the silver
• Wash in warm soapy water.
• Do not use any abrasive.
• Do not use ultrasonic cleaners
Silver is a soft metal which measures 2.5 on the Mohs hardness scale. It has a cubic crystal structure and a specific gravity of 10.50.