On the web www.portaloro.com we found an interesting article about the quality and karat of gold, one of the major concerns of the customer. We believe that will be of interest as well as being written in an entertaining and understandable.
As always, knowledge is the key to whether you buy something of value or not, but it is equally important to buy from reputable traders, experienced and have a tradition of service to their customers.
For information about the reputation of a trader must first know what you want to buy, understand the offer (type of coin and bullion available and prices), talking to other buyers who have had good or bad experiences buying gold and speak directly to all dealers in precious metals as possible and understand their work and product philosophy.
Gold has a unique color and is one of the densest metals. Normally a counterfeit gold coin is either larger or heavier or both.
An old method of checking a piece of gold was biting, because gold is a soft metal and if mixed with a base metal is harder and that the currency was checked biting gently. However, this rustic method is not a guarantee. Another classic was flipping a coin on a table and listen to the sound emitted as a gold coin has its own tone.
Some people use magnets to see a gold, whether coin or gold bullion the magnet sticks then it is more likely that it is not gold, if there is only a small magnetic attraction can be gold.
It is very difficult to forge an economic way a coin or gold bullion (small units up to 250 grams) without a test weight and dimensions quickly reveal that this is a fake. The reason is that gold is one of the densest metals (Density = Mass / Volume). The density of 24 carat gold (99.9% purity) is 19.3 grams/cm3.
 The concept of density was invented 2200 years ago by the Greek philosopher Archimedes to check fake gold, impure or manipulated. Lead is less dense than gold, and when mixed, the density of the alloy decreases. Archimedes used this data to expose to a blacksmith who wanted to deceive. Lead is very dense, cheap and easy to work for its low melting point, but is less dense than gold. To make an alloy that is just as dense as gold with metal should be equally dense, but since no metal has the same density as gold, counterfeiters try to create alloys with a combination of metal more dense and less dense than gold to get something similar to gold.
A forgery of a gold sovereign fact lead to the same thickness and diameter as the true would be a 35% lighter than the real thing. If I had the same weight and diameter as the true would be a 54% thicker than the real thing.
The difficulty lies in finding a metal heavier than gold. Almost all metals are less dense than gold and metals that are heavier are more expensive than gold. 100 years ago platinum was cheaper than gold and was used to forge gold coins, but in recent years has become more expensive than gold and is no longer an option. Some analysts say that modern counterfeiters use tungsten. Cover a tungsten core with a thin layer of gold. Tungsten has a density of 19.25 grams/cm3 and gold of 19.3 grams/cm3.
Tungsten is cheaper than gold, but not used in the past because its melting point is above 1000 degrees and there are few facilities where we can reach this temperature. To overcome this obstacle, tungsten powder is ground and mixed with other metals in a mass of correct size and format with a proportion of metals that are more or less similar to the density of gold.
Gold practitioners often recognize the gold just for the experience of working with him, only to see it and touch it, but have the following tools in case of doubt:
 1. Gold acid test
The acid test is used by jewelers and professional buyers. A jeweler or professional buyer, often recognized as a piece by touch, weight and quality of the object to check, but you may make an acid test to determine the purity of gold in doubt. In this test, gently rubbing of the gold against the stone of Arkansas (in English: Arkansas stone test), leaving a trail of gold on the stone. There are different karat acids, but the main ones to see 10, 14, 18, 20 and 22 carats.
When you apply a drop of acid and no reaction with the metal trace on the rock or metal disappears, it's gold and have a minimum karat quality for the acid to be used. Test is repeated until the gold reacts with the acid and change color or disappear. If the acid slowly dissolves gold is possible that the karat is only slightly less than the level of acid used.
Acid only checks the gold sample is analyzed and is a factor that professionals use, apart from experience, to check the quality of gold.
2. Test X-Ray-ray to measure the density of gold
X-rays are emitted through a coin or bullion and notes that go by the object and in no time you know, in percentage, the gold content, silver, copper or other metals in the area that was analyzed. This method is less interesting to see coins or ingots of up to 200 - 250 grams, but very useful for checking large jewelry or ingots possible to analyze different parts of the piece without damage. This method does not damage the part and has a very high level of assurance.
3. Fire test
The test is safer cupellation in which the part is melted in a furnace. Although this is not practical for most cases because they have to destroy the piece. Refiners and testers have adequate facilities for this type of test. This test can check up to .999 purity.
Advise: we have removed part of the article but if you want you can read the full article on web address of the next paragraph.
Source: http://www.portaloro.com/oro/como_comprobar_la_calidad_del_oro_i/ |
