For example, exposure to strong acids, such as hydrochloric acid, can dissolve gold and cause it to be destroyed. Similarly, exposure to strong bases, such as sodium hydroxide, can cause gold to corrode and become damaged. In addition to chemical reactions, gold can be damaged by physical forces.
The only way gold could truly be destroyed is through nuclear reactions. However, there does exist a way to dissolve gold using “Aqua Regia,” which is a mix of hydrochloric and nitric acids.
The most useful and important vehicle for dissolving gold is aqua regia, (royal water), composed of two parts of hydrochloric (muriatic) acid, and one part of nitric (aquafortis).
Gold neither burns nor is it flammable. It won't easily burn in a house fire because it has a melting point of 1064 degrees Celsius. Gold has the benefit of not reacting with most substances. Hence it is not easily destroyed.
Pure gold's delicate nature makes it easy to scratch and dent; as a result, pieces may easily bend or break. Therefore, other metals are often used in place of pure gold when making jewelry items that require durability.
Body oils and sweat can damage gold plating; to avoid this, clean or wipe jewelry down regularly to remove pollutants. Cleaning your gold-plated jewelry regularly will help it last longer. When doing this, use a light liquid soap and warm water. Avoid using abrasive cleaning solutions or strong chemicals.
Gold is one of the noblest—that is, least chemically reactive—of the transition elements. It is not attacked by oxygen or sulfur, although it will react readily with halogens or with solutions containing or generating chlorine, such as aqua regia.
What to do: Hold the magnet up to the gold. If it's real gold it will not stick to the magnet. (Fun fact: Real gold is not magnetic.) Fake gold, on the other hand, will stick to the magnet.
Real gold does not burn or get dark under heat. It simply melts: this is why it can be molded and shaped into different forms without losing its luster and beautiful yellow gold color. On the other hand, other metals like copper, iron, and brass will change color and get darker when exposed to flame.
Gold is one of the least reactive elements on the Periodic Table. It doesn't react with oxygen, so it never rusts or corrodes. Gold is unaffected by air, water, alkalis and all acids except aqua regia (a mixture of hydrochloric acid and nitric acid) which can dissolve gold.
Some chemicals, especially chlorine and bleach, are corrosive to gold jewelry. So if you have noticed that your gold ring, bracelet, or anklet is showing considerable wear, bleach or chlorine damage may be at play.
It's not just chlorine that can damage your gold jewellery and diamonds; saltwater can damage them too. Salt causes erosion of soldered gold, silver or platinum elements. As a result, the precious metal may weaken meaning your jewellery could potentially break.
We were reminded this earlier in February that many people aren't aware of the damage bleach and chlorine can cause to gold. Both cause a chemical reaction that disintegrates the alloys in the jewelry over time. (Nearly all gold jewelry is alloyed, because pure gold is too soft on its own.)
Gold is one of the least reactive elements on the Periodic Table. It doesn't react with oxygen, so it never rusts or corrodes. Gold is unaffected by air, water, alkalis and all acids except aqua regia (a mixture of hydrochloric acid and nitric acid) which can dissolve gold.
Gold metal dissolves in aqua regia, a mixture of hydrochloric acid, HCl, and concentrated nitric acid, HNO3, in a 3:1 ratio. The name aqua regia was coined by alchemists because of its ability to dissolve gold - the "king of metals".
Aqua regia is used to dissolve gold. Neither nitric acid or hydrochloric acid can do this alone. Nitric acid will act as the oxidizer and is used to form gold ions (Au3+).
Chlorine turns gold karat jewelry black:
Brief exposure to harsh chemicals such as chlorine bleach will have a tendency to blacken areas of the ring which contain solder, such as where a ring has been repaired or sized, and in areas where the structure of the ring is suffering from factors of age such as metal stress.
Scratch Test
For this method, get an unglazed ceramic plate or piece of tiles and scrape a piece of gold across the surface. Real gold will leave a gold-colored marking, which other metals will just leave a black streak. Be careful to only scrape the tile enough to reveal a gold marking to avoid damaging your jewelry.
Acid test.
An acid test can reveal the karat of solid gold jewelry, but it can also show whether jewelry is solid gold or gold-plated. With an acid test, a small sample of the jewelry is removed and exposed to acid to induce a color change. The resulting colors indicate which type of metal the jewelry is made of.
Fool's gold is actually iron sulfide, a non-magnetic, inexpensive and abundant material that is a byproduct of petroleum production.
Salt can be very damaging to your gold or diamond jewelry, and the main reason for this is that salt causes the metal layer of the jewelry to erode. Platinum, silver, and gold are eroded by salt, and exposure to salt over a long period of time weakens precious metals, and jewelry can break.
Real gold bullion doesn't stick to magnets. Gold isn't magnetic, so it doesn't have the ability to be attracted to a magnet. However, a magnet can be used to test if gold is real or not.
Chlorine (and bromine, also sometimes used in pools) as well as some other common household chemicals, such as bleaches, deep cleaners, detergents, solvents, etc., can and will affect karat gold causing a condition called stress corrosion.