How To Test gold Jewelry at home
Gold has a unique color and is one of the densest metals. Usually a gold coin is counterfeit or 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 it was checked gently biting the coin. 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 check an object of gold, whether coin or gold bullion to 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 size quickly reveals 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 gm/cm3.
Do I pray pure, plating, jewelery? 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 inform on a blacksmith who wanted to deceive you. 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 should be made with an equally heavy metal, but since no metal has the same density as gold, counterfeiters try to create alloys with a combination of metals 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 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 more dense metal 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 used to counterfeit 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. A tungsten core covered with a thin gold layer. Tungsten has a density of 19.25 gm/cm3 and gold of 19.3 gm/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, the 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.
Professionals often recognize gold gold just for the experience of working with him, only to see it and touch it, but have the following tools if in doubt:
Acids to test1. Gold acid test
The acid test is used by jewelers and professional buyers. A professional jeweler or buyer often recognizes the quality of a piece by touch, weight and quality of the object to check, but if you can test with acids to determine the purity of gold in case of doubt. This test is gently rubbed some of the gold against Arkansas stone (in English: Arkansas stone test), leaving a trail of gold above the stone. There are different quilatajes acids, but the main ones to check 10, 14, 18, 20 and 22 carats.
When applying a drop of the acid and no reaction with the trace of the metal above the stone or metal disappears, it is gold and have a minimum karat quality corresponding to the acid was used. Repeat the test until the gold react with 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 the 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. X-ray test-Ray to measure the density of gold
X-rays are emitted through a coin or bullion and see how many pass through the object and in no time you know, in percentage, the content of gold, silver, copper or other metals of the area being analyzed. This method is less interesting to see coins or ingots of up to 200 to 250 grams, but very useful for checking jewelery or large ingots possible to analyze different points of the piece without damaging it. This method does not damage the part and has a very high level of assurance.
3. Cupellation of gold (in English: Fire test)
The safest test is the cupellation in which the piece is melted in a furnace. Although this is not practical for most cases, because it has to destroy the part. Refiners and assayers have adequate facilities for this type of test. This test can check up to .999 purity.