Gold is one of the most sought-after precious metals in the world. For centuries, gold miners have risked their lives searching for even the smallest pebble-sized nuggets. Its unique properties, including malleability and conductivity, have made it a desirable metal to have in many industries despite its rarity. It's also popular with metals investors.
What is the Density of Gold?
Gold's density is 19.32g/cm3. The density of gold is a key factor that allows miners to find it in rivers. That makes it much denser than other metals like silver, iron, and copper.
Its density is only slightly higher than that of tungsten, at 19.25g/cm3. That's why tungsten is often used to make counterfeit gold items, including bars. Counterfeiters will take a bar of tungsten, which is not considered a precious metal (or even an expensive one), and coat it with gold.
Gold is one of the densest elements in the periodic table. To put its density into perspective, the densest element, osmium, has a density of around 22.5g/cm3. There are metals denser than gold, but none as coveted.
How Do You Find the Purity of Gold with Density?
The process of finding gold's purity with density is straightforward and involves few materials. You only need a graduated cylinder, water, and a scale, plus your gold.
Start by measuring the mass of the gold using the scale and record it in grams. Then, pour water into the graduated cylinder until it's about half full. Record the initial volume (Vi) of the water in cubic centimeters.
Put the gold into the water, taking care not to splash it and offset the reading. Record the final volume (Vf) in cubic centimeters as well.
Subtract the initial volume from the final volume and divide the mass by that difference. The equation for finding the density of gold is mass/(Vf-Vi).
Since the density of gold is 19.3g/cm3, that should be your answer if you've done the equation correctly. Because gold's density is constant, no matter its size, your answer should be the same no matter how large or small a piece of gold you have.
Does Gold Float in Water?
Pure gold shouldn't float in water. The exception here is with gold flakes and other tiny gold particles. Why is that?
Gold is hydrophobic, which means it repels water. If the weight of a gold flake is lower than that of the water, it will repel the water and float. However, this isn't the case with heavier pieces of gold—even pebble-sized nuggets—which immediately sink to the bottom.
The higher density of gold also makes it easier to find among sediment in the water, which is historically how gold miners have searched for it. Gold's density is 19 times that of water, and greater than the sediment around it. When you move a container filled with water and sediment, the denser items—including gold—sink to the bottom and become easier to spot and remove.
Gold's density means that there isn't always a need for high-tech equipment to find it. While machinery certainly makes the process more efficient and less labor-intensive, gold's natural shimmer makes it easy to spot once separated in water.
A technique some people use to make very light gold flakes sink in water is to use dish soap or Jet Dry in the water. These products disrupt the chemical bonds of the water that keep the gold afloat. If those chemical bonds break, the gold no longer repels them.
Gold Density Chart
Because the density of gold is constant, it does not factor into current gold prices. Most people buy gold based on its size and weight. The only way density helps determine the price of gold is by purity. The purest gold gets the highest price, so you want it as close to 19.3g/cm3 as possible.
The density of gold can be measured in several different ways, most of which involve keeping the same numbers and moving the decimal point. For example, when you measure gold in kilograms per millimeter, it reads as 0.01932.
On the other hand, measured in kilograms per cubic meter, you get a reading of 19,320. The only measurement that does not follow the rule of moving the decimal is when you translate to ounces per cubic inch. In that case, its density reads at 11.17.
Does that mean gold's value goes up when it reads as the highest number? No. Each measurement is equal, and while the price of gold may change daily—or even hourly—its density stays the same.
Platinum vs. Gold Density
Compared to gold, platinum is a denser and more valuable precious metal. Platinum is rarer and fewer people mine for it than for gold.
Platinum has a density of 21.4g/cm3 compared to gold's 19.3g/cm3. Because their densities are relatively similar—even though noticeably different to experts—the two are used for similar purposes, like jewelry. Often, jewelers will mix gold with other metals that are lighter in color to give the appearance of platinum.
These mixed metals create a piece much lighter in color, and closer to that of platinum, called white gold. White gold is much cheaper than platinum, so many people choose to purchase it for rings and other types of jewelry when platinum isn't an option.
Platinum is the third densest metal in the periodic table, behind osmium and iridium, the latter of which is part of the platinum family. Meanwhile, the density of gold isn't far behind at fifth, coming right after tungsten.
While platinum and gold have similar densities, the two aren't to be mistaken for one another, and you don't have to worry about someone counterfeiting gold using platinum. It would be a loss for the seller, and when it comes to the likeness between gold and platinum, density is as close as they get.
About the Author:
Clint Siegner is a Director at Money Metals Exchange, a precious metals dealer recently named "Best in the USA" by an independent global ratings group. A graduate of Linfield College in Oregon, Siegner puts his experience in business management along with his passion for personal liberty, limited government, and honest money into the development of Money Metals' brand and reach. This includes writing extensively on the bullion markets and their intersection with policy and world affairs.