Gold

This most famous of precious metals has been highly sought after and valued throughout human history not only because of its rarity and beauty, but also because of its usefullness and that it is often found highly pure in content.

Gold is very malleable (easy to work with) and durable because it does not corrode or tarnish. Its malleability can be realised if we think of how just one ounce od gold can be beaten into a flat sheet of gold leaf measuring 17 square metres.
As for its durability, we only have to consider all the historical relics such as ancient Egyptian artefacts which have survived intact for thousands of years. Considering this then, one begins to comprehend just how ancient and historically important the craft of goldsmithing is.

Pure gold is very soft and therefore liable to damage. For this reason, most gold jewellery is made of gold alloys. The content of gold alloys consists of gold and other metals. The gold content of jewellery is measured in carats (expressed fractionally as 24ths). For example, 24 carat jewellery is pure gold, while 9 carat gold has a gold content of 9/24ths, or just over one third.

What is gold?

With other numbers of metals or alloys such as copper or iron pyrite, copying gold color is easy. They will look just as the gold as the real 14k gold. So why pick 14k gold? The answer is easy. Gold does not change in color, rust or corrode or fade. Gold survives time. Also gold can be shaped to any size or shapes.

However with gold’s flexibility has a drawback. Due to its flexible nature, gold’s strength in minerals or harness is near the bottom of the chart. Because of these weaknesses, gold is mixed with one or more additional metals to make it strong. We call this alloy; they are usually copper, silver, nickel. These alloys not only strengthen the gold, but determine the color of the gold. For example, yellow gold will contain copper, and white gold will have nickel, zinc and copper is mixed in. With these concepts, gold can come in many color such as pink gold or also know as rose gold, or purple gold etc.

What does karat means in 14k?

In mineral community, precious metals measured in ounces. But this ounce system is not the system of 16 ounces to a pound which we are familiar with. Gold is instead measure what ancient troy standard. This standard is also used in pharmacists and medical profession today. Here is an example of weight system.

Karat in most in English speaking countries spells in “carat” but in U.S. carat is used to measure gem stone’s weight such as 1 carat diamond. The word carat is from ancient time when it was used from carob plant which was used to measure weight of gemstones. Carob plant’s seed was used for this process. One carob seed weighted about 200 milligrams.

Now going back to gold, purity of gold is measure from 1 to 24. 24 karat (24K) is purest form of the metal. So when you hear 18k gold, it means 18/24 karat which is 75% of gold and 25% alloy. More alloy, or lower karat in gold, gold becomes much more strong.

Gold Marks

Minimum Gold Content

To be called gold, there are minimum gold content. It varies by where you are, but in United States, item must be at least 10 K and in England and Canada 9 K and in Italy and France 18 K

Many Colors of Gold

** Some people are allergic to nickel and should not whear white gold which contains Nickel. Some manufacturers use Palladium instead of Nickel. White gold which contains Palladium will be more expensive than yellow gold or white gold but it will be less expensive than Platinum.

What causes skin discoloration with some gold jewelry?

Pure gold does not change in color or tarnish and it won’t discolor the skin. But when alloy is used to mix with gold, the gold can change and oxidize. Also human’s fat or acids in perspiration can start this change in gold. It usually gets worse in warm and damp areas where lots of salt is in the air. Sometimes, woman’s makeup can start the problem.

How to solve discoloration in gold?

1. Make a habit of removing jewelry often and cleaning the skin and jewelry.
2. Use soft cloth to wipe and clean jewelry to remove tarnish.
3. Try to switch to higher gold content jewelry. When you have discoloration gold problem in 14k gold, try to switch it to 18k gold.

What is gold coatings?

Jewelry or item less than solid 14k is considered as costume jewelry. Anything less than 10k is definitely is costume jewelry. Also you may run into term such as gold plated or vermeil jewelry. Vermeil jewelry comes into two part. When it’s vintage or antique jewelry and if its from abroad, vermeil means gold coated on bronze, brass, copper or other cheaper material.

Here is the simple figure for you to understand difference between types of gold.

When gold filled is concerned, it means 1/20th of the total weight of the piece or more. So in a sense, gold filled is better than gold plated jewelry. Gold plated jewelry is consisted of 100 millionth of an inch is chemically electronically plated. If your jewelry is “gold-flashed” or “gold-washed” means it’s plating is thinner than 7 millionths of an inch.

Silver

Though not as highly valued as gold, this soft and lustrous white metal has a proud history dating back thousands of years. Ornamental and decorative siverware has been unearthed in royal tombs dating back to 4000 BC.

Although much harder than gold, silver can be easily worked and beaten into silver leaf for decorative use. And just like gold it is long lasting and hard-wearing.

Silver has been used in jewellery and coinage throughout the ages in the form of a silver alloy. The fineness of silver items is measured as a proportion of the silver content. For instance, Sterling silver has a fineness of 925, which is to say that the silver content amounts to 92.5% of the piece. The other metal content of silver alloys used in jewellery is usually copper. Most silver jewellery has a fineness rating of 800, so there is 80% silver content and 20% copper in most silver jewellery.

High silver content is also evident in white gold. The gold content of white gold usually amounts to just over half, with silver amounting to one quarter of the content.

Silver

Anything other than gold such as silver and platinum are also alternatives to gold. Silver also has many qualities as gold. Such as lovely color and great flexibility, like gold silver have problems. Pure silver is too soft like pure gold, and to prevent that copper is added to add strength.

When you hear “sterling silver”, sterling is one of the most familiar silver alloys. Sterling consists of 925 parts pure silver and 75 parts copper. Term karat does not apply to silver. Silver is simple in a sense that silver is either sterling or not. Due to this, in silver, Federal Trade Commission prohibits the term use “sterling” or “coin silver” in reference to a plated article. Because when they say “silver plated” the plating is pure silver not like other plating metal.

Problem of silver

One major draw back of silver jewelry is that it is prong to tarnish. Silver will almost turn deepening to brown and to black. This process is quicken by today’s inner city where there is lots of air pollutions. Silver is also sensitive to alkali compounds. Which means things like sea air can tarnish the silver.

Solution

Best solution for tarnished silver is to buy silver cleaning chemical. And use soft cloth and apply these chemicals to clean your jewelry. Also toothpaste does a job too.

Platinum

Although artefacts containing platinum have been found dating back to the times of the ancient Egyptians, it is thought that they were unaware of this precious metal being present in the mainly gold pieces it has been found in. The first discoveries which identify Platinum as a distinct precious metal occurred in 16th century Columbia. Indeed, the name Platinum dates from this time, when Spanish invaders noted its resemblance to silver ; the word platinum coming from the Spanish, 'platina del Pinta'.

The demand for platinum in jewellery has greatly increased in recent times, with particularly high demand in Japan.

Most of the world's platinum comes from the Transvaal area of South Africa and Russia.

Bronze

TThe history of mankind's use of bronze stratches way back to 3000 BC. Bronze is often an alloy made up of the metals copper and tin, although in recent times bronze has also been made using aluminium, manganese or zinc instead of tin.

Being very hard and durable yet easy to cast, bronze has been widely used throughout history for coinage, tools and weaponry. Iron hjas taken the place of bronze in many uses over the centuries because it is more widely available, reather than it being significantly better or more suited to its uses.

Assaying

The content and value of precious metals is determined by processes of chemical analysis called assaying. The history and formulation of the processes involved is rooted in the work of ancient alchemists and goldsmiths who would subject base metals to heat.

Assaying by fire is still the most economical methos of assaying precious metals, even more so than modern methods such as spectrographic analysis because of the amounts of the metals needed to carry out the tests.

The fire assaying method consists of 6 steps :

1. Sampling. A representative sample is taken.

2. Fusion. The sample is then melted along with flexes and other agents to collect elements of precious metals in droplets of lead. These are then cooled to produce a 'lead button'.

3. Coppelation. The 'lead button' is then melted and the impurities are oxidised. Beads of precious metals then form.

4. Weighing. Beads of gold and silver are then weighed to determine their gold and silver content. Platinum is present in quantities to small to weigh however.

5. Parting. Each bead is then trated to dissolve out the silver content.

6. Weighing. Finally, the remianing gold content is weighed andthis mesurement is subtracted from the gold-silver bead weight previously measured. This calculation then gives us the weight of the silver content.