Gold is often called the "king of metals." Humans have always adored, appreciated, and prized it for centuries for its beauty, rarity, and durability. The metal is precious and is found in nature in its pure form. Is gold a pure substance, though?
Gold has been used for jewelry for centuries. It has been a popular choice because it does not rust or tarnish. Gold also has a beautiful color that does not fade over time. In addition, gold is very durable and can last for many years.
But do we use gold in its purest form? Is it an element or a mixture of several components? Let's get to the bottom of this shiny object.
Image by Goldaniza.Com
How to Measure the Purity of Gold
The standard unit for measuring gold's purity is karat. There are several gold varieties in the market, ranging between 24 and 10 karats.
The purest form is 24K gold, which contains 99.9% of gold. Pure gold is too soft to hold its shape, so there's no way to make jewelry with 24K gold. The high-quality gold jewelry pieces are 22K, containing 91.6% gold and 8.4% metal alloy.
Apart from the karat variations, there are other types, including rose gold and white gold.
An alloy of pure gold and copper is rose gold, containing 75% gold and 25% copper. Rose gold has a pink or reddish hue and is often used for fine jewelry, such as rings, earrings, and necklaces.
Image by Cartier
White gold is also an alloy that contains 25% of nickel, silver, or palladium, or a mix of two or more of these elements. It has a light gray color and is mostly used as a cheaper alternative to platinum.
There is also blue gold (54% indium), black gold (25% cobalt), green gold (a natural alloy with 27% silver), and purple gold (20% aluminum). These gold types have widespread usage for making ornaments and jewelry.
Another variation is gold vermeil, a sterling silver piece with a 10k and 2.5 microns thick gold plating. It's not actually gold but silver with a golden layer.
Gold is found in nature in a pure form, but it is also found in certain minerals and ore deposits. The most common gold ore is quartz, which contains small amounts of gold.
Image by Virrage Images via Shutterstock
is Gold a Substance? What Does Chemistry Say?
Gold's use has been versatile since its discovery, unlike many other gemstones and rare, valuable metal elements. People applied it for religious ceremonies, medicinal treatments, mental well-being, and food elements.
Not to mention its incredible popularity as jewelry, both in the ancient and modern time.
So, you might be wondering what gold actually is. Is it a substance, element, or compound?
An element is something that contains only one atom type and nothing else. So, there should be only one atom type in gold, not multiple gold atoms.
We can consider gold as an element because Aurum (Au) is the only atom found in it. Similarly, a diamond is an element because it consists of only the carbon atom.
On the other hand, a compound is the chemical bonding of two or more elements. It will lose its characteristics if you break it down. For example, water is a compound, and breaking it down will yield oxygen and hydrogen.
You can call both an element and a compound as a substance. So, we can say that gold falls into the "element" category of a substance.
Image by Lea Rae via Shutterstock
is Gold a Pure Substance? Explaining the "Purity" in Gold Standards
Yes, gold is a pure substance.
A substance is pure when there is no other type of element or compound in it. Gold is composed of only Aurum (Au) and nothing else. Also, you can find this element in nature in its pure form.
However, it does not mean that every gold material you see is pure. The gold materials we see in our everyday life are rarely pure gold.
A couple of standards are there to measure gold's purity, but karats (based on considering the material as 24 parts by weight) are the most popular. 24K offers the finest quality in this system, but it also has some variations.
Image by Lea Rae via Shutterstock
For example, .990 fine gold is considered 24K, while the material is available in even more refined forms. However, you will find 999.99 or "five nines" fine and 999.9 or "four nines" fine levels of purity when buying gold coins.
The most common is the gold bullion coins with a purity of .917 fineness. So, it's evident that the highest purity level is quite rare in both gold jewelry and coins. You have a zero chance to see 100% pure gold outside a laboratory.
Image by James St. John via Wikimedia
is Gold a Pure Substance or a Mixture?
So, when you look at a piece of gold jewelry, what should you call it? A substance or mixture?
We have already discussed what a substance is. Now get to the bottom of this mixture part.
So, we've already discussed what compound is. A mixture forms when you mix up two or more compounds. For example, water and salt are two compounds, and together they form a salty water mixture.
Image by Richy via Shutterstock
In fact gold is so pure.. that gold is edible!
You can separate the compounds and elements in a solution through a chemical process, but this is not possible for a pure substance. Evaporation will separate salt and water, and then you can further separate these compounds into elements.
However, pure substances like gold or oxygen will not break down into other elements. Also, the chemical properties of a pure substance, whether it's an element or compound, are consistent, unlike a mixture that shows variations.
Image by Saran Insawat via Shutterstock
Gold Atoms Make Pure Gold
While pure gold is beautiful, it is also very soft and can easily be scratched or bent. Also, it's a ductile metal, meaning you can give it a completely different shape without breaking it down. For this reason, gold jewelry is usually made with a mixture of gold and other metals, including copper, nickel, and silver.
Blending one or multiple metals adds strength to the gold, making it more durable. Gold jewelry that is made with a mixture of gold and other metals also tends to be less expensive (in terms of karat weight) than pure gold coins and bars of the same weight.
So, when gold is mixed with other materials for enhancing its durability and strength, you can call it a mixture. Depending on the percentage of different materials in the alloy, the karats of golden materials are determined.
Image by Ben Garelick
The purest gold jewelry is 22K (containing 91.67% of gold), as making them with 24K is impossible because of pure gold's softness. The popular karat preferences for golden jewelry vary from one country to another.
Indians love their ornaments to be 22K, while Europeans mostly purchase 18K jewelry. It seems that Americans don't bother much with purity since most gold jewelry in the USA is 14K.
Image by Cartier
is Gold Homogeneous or Heterogeneous?
Despite gold being a pure substance, we mostly see it as a mixture. For example, any gold jewelry is a mixture. So, you might be wondering what kind of mixture it is - homogeneous or heterogeneous.
In fact, gold can be both.
A homogeneous material is something that has a uniform chemical composition. The chemical examination will reveal the same elements and/or compounds across their bodies. Heterogeneous mixtures have different compositions in their bodies. For example, a combination of oil and water is a heterogeneous mixture.
Image by Tiffany
Gold jewelry, where gold is mixed with metals, is a homogeneous mixture. For example, all jewelry pieces made of a mix of gold and copper will produce the same results in chemical analysis.
On the other hand, gold could be heterogeneous too when it's blended with another material, and the two are not mixed well. It can happen in laboratories, and such materials can be found in nature too. Mixtures of gold and minerals are heterogeneous because these materials don't bond well.
Gold is a pure substance and one of the most valuable and sought-after metals globally. Thanks to its many unique properties, it has been used for centuries in jewelry, coins, and other decorative items.
In addition, gold is also a popular investment choice, as it does not lose value during times of economic instability. If you are considering buying gold, be sure to do your research first to find the best option for you.
Image by James St. John via Flickr
FAQS About Gold Substance
is Gold a Mineral?
Gold is both mineral and metal. Minerals are crystal formation that occurs naturally. Metals also naturally occur in minerals and have a crystal-like chemical structure in the solid form. Gold has properties of both elements.
is Gold a Rock or Metal?
Gold is both metal and rock. Since rock is a solid mass of minerals or mineral-like matter and gold is often found in quartz stone, a kind of rock, you can consider gold as a rock.
Image by 8180766 via Pixabay
is a Gold Bar a Pure Substance?
Yes, a gold bar is a pure substance. However, 100% pure gold does not exist, except in laboratories. Golden bars are the standard of purest gold that we can have.
is Gold Magnetic?
Gold is not magnetic, at least not in its natural state. Its non-magnetic property has long been used to differentiate real gold from fake ones. However, a 2016 study found that heat application can make gold show magnetic attributes.
Tags: gold atoms, element gold, pure metal, other substances, copper metal, same composition, gold mixed, chemical element