What Is the Melting Point of Gold?
Posted on February 15, 2021
Gold has been put on a pedestal ” or used to make said pedestal ” for thousands of years. In the grand scale of time, our understanding of the properties of gold is fairly new. Before we get into gold's melting point and density, it's a good idea to have an understanding of what these terms mean.
What Are Melting Points and Density?
Melting point and density are important terms when working with metals of any kind. They often decide what someone can do with a certain metal, especially gold.
What Is Melting Point?
Every metal has a melting point at which it moves from a solid to a liquid state. The melting point of a substance is measured in degrees Fahrenheit, Celsius, or Kelvin. The higher the temperature, the closer the substance gets to its melting point. After it reaches that point and turns to liquid, any additional heat will continue to raise the temperature of the liquid until it reaches its boiling point. [1] When this process is reversed, the melting point is referred to as the freezing point.
The concept of the melting point has been around since ancient times. Early metallurgists found that impurities and many of the other metals found in gold could be burned away before the gold itself would melt. Gold's hardness helps people mine it from less dense rock and then cleanse the precious metal.
What Is Density?
Density is the mass of a unit volume of a substance, represented by the formula d = M/V. To find density, you divide the substance's mass (how heavy it is) by its volume (how much space it takes up). The final number is its density, which tells you how much mass a substance fits into a given space. [2]
A gold item was actually the catalyst that led to the discovery of the scientific concept of density. Greek Mathematician Archimedes in 250 B.C. was tasked by the king of Syracuse to find out whether a golden crown was real. Archimedes measured the crown's density by measuring the water it displaced when placed into a tub, a method still taught in schools today. [3]
What Are Gold's Physical Properties?
Gold's natural beauty and relative rarity make it one of the most sought-after substances on Earth. Additionally, gold's physical properties also make this metal one of the best for creating jewelry and producing some industrial and technological components.
The Melting Point of Gold
Pure gold's melting point is 1,948 degrees Fahrenheit, or 1,064.4 degrees Celsius. Here is a comparison of some common and precious metals:
- Zinc - 787.2°F
- Silver - 1,763°F
- Gold - 1,948°F
- Copper - 1,984°F
- Nickel - 2,651°F
- Palladium - 2,831°F
- Platinum - 3,215°F
The melting point of a piece of gold varies if it's alloyed with another metal. This is where the karat comes into play. Pure gold is 24-karat. Gold that is 50% alloyed with another metal is 12-karat gold. Divide the number of karats a piece of gold has by 24 to find its percentage of purity.
Density
Gold's high density makes it one of the heaviest metals. It is, in fact, a heavy metal by designation. Gold's density is 19.3 grams per cubic centimeter. Gold is particularly heavy compared to its volume. To put it into perspective, here are some comparisons:
- Pinewood - 0.35-0.55 grams/cubic centimeter
- Diamond - 3.52 grams/cubic centimeter
- Iron - 7.87 grams/cubic centimeter
- Lead - 11.3 grams/cubic centimeter
- Gold - 19.3 grams/cubic centimeter [4]
- Platinum - 21.45 grams/cubic centimeter
- Iridium - 22.4 grams/cubic centimeter
- Osmium - 22.6 grams/cubic centimeter
Let's put this another way: Say you have the lightest version of the 2019 Honda Civic, which weighs 2,762 pounds. If you were to drive that Civic on to a large scale, you would only need 2.29 cubic feet of gold to balance that scale. This is because gold's molecules are more tightly packed together than most other substances, except for even heavier metals.
How Do the Physical Properties of Gold Inform Its Applications?
Gold's unique properties caused it to be sought after by humans. From its face-value attractiveness to its ability to be shaped into ways that please the early peoples who collected it, gold's physical properties destined it to become a precious metal.
Malleability
Gold can be shaped very easily in comparison to other metals. In fact, 1 ounce of gold can be hammered out into a sheet of 100 square feet. [5] However, this high malleability also means that gold is scratched very easily, which is why it is often alloyed with other metals to strengthen it.
Noble Metal
One of the reasons gold is so tough is because it is one of the noble metals. Noble metals are exceptionally resistant to corrosion and oxidation. This is arguably another one of the biggest reasons gold has been collected and revered for millennia. Though it's susceptible to scratches, gold holds up very well against the elements, corrosion, and heat. These properties make it naturally useful when making coinage and jewelry. This imperviousness also makes it stand up against rust and the tarnishing that silver sometimes experiences.
Reflectivity
Gold is naturally lustrous because it does not absorb light. This gives gold a more reflective surface that makes it appear more shiny and sparkling than some other metals. The visors of astronauts' helmets are coated in a very thin layer of gold, which helps reflect sunlight and heat. [5]
Gold has withstood the test of time in terms of its value to investors and anyone else looking for security in their assets. Whether it's through pure gold bullion or scrap gold, this precious metal will likely maintain its value for centuries to come.
Article sources:
1. Encyclopedia Britannica, Inc. 'Melting point,' https://www.britannica.com/science/melting-point. Accessed Sept. 10, 2020.
2. Encyclopedia Britannica, Inc. 'Density,' https://www.britannica.com/science/density. Accessed Sept. 10, 2020.
3. Live Science. 'Eureka! The Archimedes Principle,' https://www.livescience.com/58839-archimedes-principle.html. Accessed Sept. 10, 2020.
4. Good Science. 'Density of Solids, Liquids and Gases,' https://www.goodscience.com.au/year-8-chemistry/density-of-solids-liquids-and-gases/.. Accessed Sept 10, 2020.
5. American Museum of Natural History. 'Gold Fun Facts,' https://www.amnh.org/exhibitions/gold/eureka/gold-fun-facts. Accessed Sept. 10, 2020.
