GOLD –The enduring metal.
Two thousand years ago, Pinder, the Greek, wrote: “Gold is the child of Zeus – neither moth nor rust can devour it.”
Wars have been fought over it, love has been declared with it. As an investment, gold has outperformed all equities since 2012. Mankind will forever treasure gold because of its historic and emotional value. Today nearly 80% of mined gold is used to make fine jewellery.
Native gold is normally found as minute grains in rocks or river beds and normally is not pure but contains a few percent of silver. It is refined to pure gold (24k) which is too soft to be used in jewellery because it bends easily and cannot hold gemstones securely. The goldsmith thus adds silver and copper in specific proportions to pure gold to make alloys such as 18k, 14k and 9k gold.
18k gold : Pure gold = 75% 9kt gold: Pure gold = 37.5% silver and copper =25% silver and copper = 62.5%
The higher the copper content of the alloy, the redder the gold will be as in pink or rose gold. 18k yellow gold is stamped, i.e. hallmarked as 750. 14k gold is stamped 538 while. 9k gold is stamped 375.
9k jewellery wears quicker. We only can admire antique jewellery nowadays because it was manufactured in 18k gold or platinum.
WHAT IS WHITE GOLD ? In the 1990’s, platinum and white gold became favourite metals for jewellery.
White gold alloys are produced by adding silver, nickel or palladium to pure gold. Nickel white gold can tarnish, is allogenic to some and thus needs to be plated with a white metal called Rhodium – to give it a “whiter” look. Rhodium plating wears off and has to be redone every few years. Most mass-produced white gold jewellery contains some nickel.
We thus prefer to use palladium-based white gold alloy for handmade items, because: Palladium belongs to the Platinum group metals, is acid resistant and does not tarnish. It is pliable, can be polished to a high white lustre and does not need Rhodium plating. Palladium white gold is more expensive than Nickel white gold as it is a heavier alloy and more difficult to process. Its melting temperature is 1480 ᵒC compared to 995 ᵒC of Nickel white gold.
IN CONCLUSION: 18k is definitely the best quality. It has a higher specific gravity, therefore is heavier than the same jewellery item in 14k or lower. If you can afford it, you would not only have the better gold, but also more of it and can pass it on as an heirloom.
NOTE: the prices of precious metals are volatile and may change at any time.
WHAT IS BLACK GOLD ?
You have heard of black diamonds, but black gold ? Never.
Goldsmiths have used the following methods to change the surface of gold into a black or grey colour.
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- Electroplating using “black” rhodium or ruthenium.
- A blackish “patina” can be produced by applying sulphur and oxygen containing compounds (liver of sulphur) to gold.
- Plasma assisted chemical vapour deposition of amorphous carbon and the controlled oxidation of gold containing chromium and cobalt results in a black gold layer.A recent technique, called femtosecond laser pulsing, deforms the surface of gold into nano structures. These immensely small structures increase the surface area which absorbs all light that falls on it rendering the surface a deep black colour. A new black metal used for jewellery is an oxidized cobalt-chrome alloy.Already in the 7th century BC, in antique Rome, gold wire was used to fasten tired teeth. Gold was used for the first time in the 16th century, to fill teeth cavities.The Aztecs name for gold was “Teocuitlatl”, which means translated: “excrement of the gods”. The Asteroid Eros contains more gold than ever has been mined from the Earth.
- Gold has always been treasured by mankind and therefore recycled for thousands of years. 85% of all the gold ever mined in the world is still in use. It is estimated that approximately 10 billion tons of gold is dissolved in the oceans.
- WHAT IS PLATINUM ? – THE ULTIMATE PRECIOUS METAL
- The platinum we use comes from The Merensky Reef, a platinum rich layer in the Bushveld Igneous Complex which was formed approximately 2000 million years ago in the North West Province of South Africa. These deposits account for more than 80% of the world’s platinum reserves and have been mined for more than 80 years. The bulk of these riches occurs on land of the BaFokeng people near Rustenburg and has played a significant role in their economic development.
- WHY IS PLATINUM JEWELLERY MORE EXPENSIVE THAN GOLD JEWELLERY ? Because:
- A platinum item contains 95% pure platinum compared to 75% pure gold in an 18k item.
- Labour and refining costs are much more for platinum than for gold. Platinum melts at 1769 ºC and gold at 1063 ºCelsius.NOTE: Mass produced (casted) platinum jewellery should cost less than individual pieces made by hand, Platinum jewellery that contain less than 95% pure platinum are hallmarked platinum and should thus be less expensive than an item stamped Pt950. PHONE NOW FOR A QUOTE ON YOUR PLATINUM RING.
- WHAT IS PALLADIUM ? – THE MODERN PRECIOUS METAL Palladium is one of the Platinum Group Metals and is extracted from the same ore that produces platinum. It has been used as a precious metal in jewellery since 1939, and to make modern white gold alloys. The price of palladium is far more than that of platinum.
- A platinum item weighs 30% more than a similar item in 18k gold. Although the raw metal price of platinum is today less than that of gold, the final price of a platinum item can be equal to that of a similar item made in 18k gold.
- Rheumatoid arthritis has been treated for decades with injections of gold solution. Why the metal has an anti-inflammatory effect is still not clear to medical professional.
- The visor of astronaut’s helmets is covered with a thin layer of gold to protect the eyes of the astronauts from sun’s radiation.
- 20% of the world’s jewellery gold has been woven into Indian Saris – a women’s garment.
- Australian scientists discovered micro-organisms, which obviously feed on gold. The mining industry is making use of this: The microbes collect traces of gold from the rocks and concentrate them to bigger nuggets.
- The first documented gold discovery dates back to 1799 in North Carolina USA. The lump of gold weighed 3.2kg and was used for three years as doorstep until a jeweller recognized the precious piece and bought it for 3.50 dollars.