In this blog post, we’ll take an easy-to-understand look at everything from why couple rings are worn on the ring finger to the differences between 24K, 18K, and 14K gold, the necessity of gold alloys, the principles behind the colors of white gold and rose gold, and the differences between white gold and platinum.
Why Are Couple Rings Worn on the Ring Finger?
Stories linking fingers to human relationships have been passed down across many cultures, and one of the most widely known explanations compares the fingers to family members. It is said that the thumb represents parents, the index finger represents siblings, the middle finger represents oneself, the ring finger represents a spouse, and the little finger represents children.
There is also a simple experiment that uses this analogy. If you place your palms together, fold your middle fingers inward, and touch the tips of your other fingers, then try to separate your fingers one by one, you’ll notice that the thumb, index finger, and little finger come apart relatively easily, while the ring finger seems to resist separation. This is said to symbolize that a spouse is someone who cannot be easily separated from in life, and this is how the custom of wearing a ring on the ring finger originated.
Furthermore, in the West, the belief that the “Vena Amoris” (the vein of love) runs from the ring finger to the heart has been widespread for a long time. Although this is not true from a modern medical perspective, this belief is known to have influenced the spread of the culture of wearing wedding rings and matching rings on the ring finger. Therefore, it is appropriate to understand that the reason for wearing a ring on the ring finger today stems from cultural symbols and traditions passed down over many years, rather than from scientific fact.
The Meaning of “K” and Why It Became “24K”
The “K” mark commonly found on gemstones and gold jewelry stands for “karat,” which indicates the purity of gold. Although the spelling differs from “carat,” which refers to the weight of gemstones, both terms are historically known to have originated from the carob seed.
According to the traditional method of expressing gold purity as a fraction of 24, pure gold is denoted as 24K. Therefore, 18K refers to an alloy containing 18/24, or approximately 75.0%, gold, while 14K refers to an alloy containing 14/24, or approximately 58.5%, gold. The higher the “K” number, the higher the gold purity; the lower the number, the higher the proportion of other metals.
Recently, many products have begun using numerical purity designations such as 999 or 999.9 instead of 24K. This is an international notation system intended to indicate the gold content more accurately, and it is often used alongside the 24K system depending on the country and manufacturer.
Why create an alloy instead of using pure gold as is?
Pure gold is a precious metal with a beautiful luster and excellent corrosion resistance, but physically, it is a very soft metal. In fact, pure gold is so malleable that it can be easily deformed—to the point where pressing it with a fingernail or a hard object leaves an indentation.
These properties can be explained at the atomic level. A metal’s strength is influenced by various factors, including atomic arrangement, metallic bonding, crystal structure, and the movement of dislocations; pure gold allows dislocations to move relatively easily, making it highly deformable.
Therefore, for jewelry that requires strength and durability, alloys are created by mixing various metals—such as copper, silver, palladium, nickel, and zinc—in appropriate proportions. When different atoms are mixed within the metal, the movement of dislocations is hindered, resulting in increased strength and hardness, and making the metal more resistant to scratches and impacts.
The purpose of creating alloys is not merely to make the metal harder. Various metals are combined not only to reduce wear and extend the jewelry’s lifespan but also to achieve a wide range of colors and improve workability, enabling the creation of intricate designs. As a result, jewelry can embody both beauty and practicality.
How are rose gold and white gold made?
The color of gold depends on which metals are mixed in and in what proportions. In particular, alloys like 14K gold—which contains about 58.5% gold—can produce a variety of hues depending on the types and proportions of the remaining metals.
For example, increasing the copper content results in pink gold or rose gold with a reddish tint, while adding appropriate amounts of silver or palladium creates bright-toned white gold. Most products available on the market use a combination of metals to achieve the desired color, strength, and durability.
When describing the composition of an alloy, a composition chart indicating the content of metals such as gold, silver, and copper is often used. These charts help explain how different colors and physical properties emerge based on specific compositions, and they demonstrate that even within the same 14K category, a wide range of hues can be achieved depending on the ratio of metals used.
On the other hand, alloys like 18K, which contain 75% gold, retain a strong natural yellow hue, resulting in a relatively narrow range of color variations. Therefore, even when the same metals are added, the range of color variations is more limited than with 14K, and it is relatively difficult to achieve very vivid pink or bright white tones.
Are white gold and platinum the same metal?
Just because the name includes “white” does not mean that white gold is the same as platinum. White gold is fundamentally an alloy with gold as its main component, mixed with metals such as palladium, silver, nickel, and zinc to give it a silvery appearance. Additionally, most white gold products are often rhodium-plated to achieve a brighter and more vivid white color.
In contrast, platinum is a precious metal composed of the element platinum itself—an independent metal with atomic number 78. It has a natural silvery-white color and is widely used as a material for high-end jewelry due to its excellent corrosion resistance and durability.
Over time, the rhodium plating on the surface of white gold may wear off; in such cases, re-plating can restore the bright color to its original state. Platinum, on the other hand, is not a metal that relies on plating for its color, so its surface texture naturally changes over time.
Therefore, while white gold and platinum may look similar at first glance, they differ in several aspects, including the materials used, physical properties, weight, care methods, and price.
Important Points to Keep in Mind When Choosing Couple’s Rings
So far, we’ve examined why couple rings are worn on the ring finger, the differences between 24K, 18K, and 14K gold, the reasons for using alloys instead of pure gold, the principles behind the colors of pink gold and white gold, and the differences between white gold and platinum.
A ring is not merely a beautiful piece of jewelry; its durability, color, and comfort vary depending on the material, purity, and type of alloy. Therefore, rather than comparing only price or design, it’s important to make your choice by considering your lifestyle, personal taste, how often you’ll wear the ring, and how you’ll care for it.
In particular, since couple’s rings and wedding bands are often worn daily for many years, examining the proportion of pure gold, the ring’s strength, and ease of maintenance will help ensure your satisfaction. Additionally, since some products—such as white gold and platinum—look similar but are made of different materials, it’s best to fully understand the characteristics of each before making a purchase.
Rings are both a symbol of your love for one another and a cherished keepsake that will accompany you for many years. By keeping the information presented in this article in mind when selecting a ring, you can go beyond simply choosing a design and instead select the material that best suits your personal taste and lifestyle, allowing you to make a wiser choice for a couple’s ring that you’ll be happy to wear for years to come.
