Gold. Gold ranks high in physical properties that matter in jewelry. It will not tarnish or rust, and it is the most corrosion-proof and oxidation-resistant metal. Although it is very strong, gold is the most malleable of all metals.
Palladium and platinum are always harder than gold alloys and silver. Palladium is less dense than platinum, so platinum is the most durable metal overall. The best rule of thumb is to always wear the same metal and carat next to each other for even wear over time. Rhodium is a member of the platinum family.
Gold is soft because the atomic nuclei in gold is held together by a cloud of electrons. This cloud drifts through the gold structure instead of having one a set of electrons dedicated to one nucleus. The force between the nuclei and the cloud of electrons is called a metallic bond. That's the scientific explanation.
Hence, platinum is stronger than gold.
Gold is a chemical element with the symbol Au (from Latin aurum 'gold') and atomic number 79. This makes it one of the higher–atomic-number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal in pure form.
Tungsten, which is Swedish for "heavy stone," is the strongest metal in the world. It was identified as a new element in 1781. It is commonly used to make bullets and missiles, metal evaporation work, manufacturing of paints, creating electron and Television tubes, and making glass to metal seals.
In their pure forms, gold and silver happen to be very soft metals—soft enough that you should be able to mark them with your teeth. According to the Mohs hardness scale—which relates pairs of materials according to which one will scratch the other first—gold scores a 2.5 and silver, which is harder, a 2.7.
'Aqua Regia' is a mix of hydrochloric acid and nitric acid, most commonly in a 3:1 ratio. This is believed to be the only solution known that can "dissolve" gold.
If translated into numbers, platinum—for all of its known deposits—is considerably more rare than gold and is the rarest metal of all. And it is, truly, a gift from the heavens.
Rhodium. Depending on the fluctuations of the world market, rhodium is often the most expensive metal in the world.
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.
Metals like Gold and Iron are hard and dense . They are malleable and ductile. They are very tough and it's nearly impossible to be cut with a knife. Proper machines and techniques are used to cut such metals.
Pure gold is virtually indestructible. It will not corrode, rust or tarnish, and fire cannot destroy it. This is why all of the gold extracted from the earth is still melted, re-melted and used over and over again.
Copper, brass, and bronze do not rust for the same reason as aluminum. All three have a negligible amount of iron in them. Therefore no iron oxide, or rust, can form.
Platinum: Despite being nearly identical in appearance, platinum is more valuable than gold. Platinum's high price point can be attributed to its rarity and density as precious metals are often priced by their weight.
The average concentration of gold in Earth's crust is 'very, very low,' at 4 parts per billion. In its elemental form, gold is significantly rarer than diamonds.
The rarest metal on earth is actually francium, but because this unstable element has a half life of a mere 22 minutes, it has no practical use. Tantalum, on the other hand, is used to make capacitors in electronic equipment such as mobile phones, DVD players, video game systems, and computers.
In terms of abundance in the Earth's crust, the rarest metals are: gold, platinum, osmium, iridium, palladium, ruthenium, rhodium, tellurium and rhenium.
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.
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 will not get affected by water but it can lose its shine over time and it is recommended to take your jewelry off before taking a shower.
Many people are curious to know why in the old days it was common to bite gold coins – or other kinds of items made of gold – to confirm whether or not they were real. This practical and crude method was used for the authentication of gold since this metal is very malleable.
Pirates biting gold
The rationale for biting a coin was the supposed widespread dissemination of gold plated lead coins in the 19th century. Since lead is much softer than gold, biting the coins is a sensible test for counterfeiting.