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What is the color of real gold necklace?

Gold has been treasured and revered throughout human history. Its unique properties like malleability, shine, and resistance to corrosion make it ideal for jewelry and ornamentation. The rich, warm color of gold is universally recognized and associated with luxury. But what exactly is the true color of real gold jewelry like gold necklaces? Let’s take a deep dive into the science and nuances behind the color of this precious metal.

The Science Behind Gold’s Color

The origin of gold’s distinctive color lies in its unique atomic structure. Gold is an element with the atomic number 79 and has one valence electron in its outermost orbital. The sea of electrons flowing around the gold nucleus absorbs certain wavelengths of light, while reflecting others. This selective absorption and reflection is what gives gold its characteristic yellowish color.

When white light, which contains all the colors of the visible spectrum, shines on gold, the electrons in the gold atoms absorb the blue end of the spectrum. Blue light has a higher frequency and energy than red light. The energy from the blue light gets transferred to the electrons, causing them to jump to higher energy levels temporarily. But the excited electrons soon return to their original lower energy states by releasing energy. The released energy is in the form of yellow and red wavelengths of light, which get reflected back, giving gold its warm, yellowish glow.

Variations in Gold’s Color

While pure gold has a consistent yellow tone, the color of real gold jewelry and ornaments can vary depending on several factors:

Karat

Karat refers to the purity level of gold. Pure gold is 24 karat, while lower karat numbers contain alloy metals like copper, silver, or palladium. Alloying gold with other metals creates differences in color:

Karat Gold Content Color
24K 100% Bright yellow
22K 91.7% Yellow
18K 75% Yellow with slightly rosier tint
14K 58.3% Light yellow to yellow-gold
10K 41.7% More golden than yellow

Lower karat gold contains higher percentages of copper and silver, giving the gold a paler, whiter appearance. 14K and 18K are commonly used in jewelry today.

Oxidation

Although gold does not corrode or rust like other metals, it can undergo oxidation over time. This can make the surface of gold jewelry look less yellow. Exposure to household chemicals, saltwater, and even body oils can cause gold oxidation. The gold takes on a paler and more muted yellow tone. Gentle polishing can help restore the original bright color of lightly oxidized gold.

Rhodium Plating

To prevent oxidation and enhance brilliance, white gold jewelry pieces are often plated with rhodium. This is a silvery-white noble metal from the platinum family. The rhodium plating gives white gold a whiter, shinier appearance. But it can wear away over time, revealing the original yellow-hued white gold underneath. Rhodium plated white gold necklaces may need re-plating every 1-2 years to maintain their original color.

Rose Gold

The pinkish hue of rose gold is achieved by alloying yellow gold with copper. Increasing the copper content from the typical 5% to 20-25% gives gold a rosy pink color. Varying the ratio of gold to copper can create different shades of rose gold, from subtle pink to deep red. The copper makes rose gold more prone to oxidation compared to yellow or white gold. But regular polishing can keep rose gold necklaces looking vibrant.

Assessing the Color of Gold Jewelry

There are a few simple ways to judge the true color of a real gold necklace or ornament:

Look Inside the Jewelry

Examine openings like clasps, links or posts that go inside the jewelry. These protected inner surfaces will show the true color of the gold, without any effects from oxidation or plating.

Rub the Gold on a Testing Stone

Jewelers use black testing stones made of materials like basalt, slate or granite. Rubbing gold jewelry on the stone creates a metallic streak. The color of this streak reveals the karat and hue of the gold. A pale greenish-yellow streak indicates lower karat yellow gold. Pure 24K gold leaves a bright shiny yellow streak.

Examine the Hallmark Stamp

Real gold jewelry is stamped with a hallmark indicating its karat, usually as a number like 417, 585 or 750. This karat marking legally verifies the purity of the gold. Studying the hallmark can clarify if the gold color has been altered by oxidation or plating.

Do an Acid Test

Professionals sometimes use nitric acid or sulfuric acid solutions to check gold karat. Applying a drop of the acid on an inconspicuous spot will dissolve base metals. But pure gold is inert and withstands corrosion by acids. The amount of acid-resistant gold left behind indicates the karat.

Caring for Gold’s Color

Gold’s captivating color can last forever if you look after your gold necklaces and ornaments properly:

  • Store pieces separately to prevent scratches and tangles that can lead to gold loss.
  • Clean with gentle jewelry cleaner, mild soap and soft brush.
  • Rinse and dry thoroughly after cleaning.
  • Remove gold jewelry before swimming or household chores.
  • Get white gold re-plated when it starts looking yellow.
  • Have rose gold professionally polished if it loses its pink luster.

Conclusion

Gold’s rich and warm yellow tone has an enduring allure. But the true color of real gold jewelry depends on its karat, alloy metals, and how it has been handled over time. Understanding the effects of oxidation, plating, and copper content allows you to better evaluate the color of gold necklaces and ornaments. With proper care and maintenance, the unique color of your gold jewelry can sparkle forever.