Gemstones have been valued for their beauty and rarity for thousands of years. One of the key factors that make gemstones so desirable is their color. Gemstones can come in a wide range of colors, from deep reds and blues to vibrant greens and yellows. But what is it that gives gemstones their unique colors? In this article, we will explore the connection between the color spectrum and gemstone colors.

The Color Spectrum

Before we can delve into the relationship between the color spectrum and gemstone colors, it's important to understand the color spectrum itself. The color spectrum refers to the range of colors that are visible to the human eye. This range is typically divided into seven colors: red, orange, yellow, green, blue, indigo, and violet.

Each of these colors corresponds to a specific wavelength of light. Red has the longest wavelength and violet has the shortest. When white light (which contains all of the colors in the spectrum) is passed through a prism, it separates into its component colors, revealing the full spectrum.

Gemstone Colors

Now that we have a basic understanding of the color spectrum, let's turn our attention to gemstone colors. Gemstones are typically classified by their color, with each color corresponding to a different type of gemstone. For example, red gemstones include rubies and garnets, while blue gemstones include sapphires and aquamarines.

But what is it that gives gemstones their unique colors? The answer lies in the way that light interacts with the gemstone. When light enters a gemstone, it can be absorbed, reflected, or refracted. The specific way that light behaves within the gemstone determines its color.

For example, some gemstones get their color from the presence of certain impurities within the stone. The presence of iron, for example, is what gives peridot its distinctive green color. Other gemstones, like diamonds, get their color from structural defects within the crystal lattice.

The Relationship Between the Color Spectrum and Gemstone Colors

So how does the color spectrum come into play when it comes to gemstone colors? The answer lies in the concept of complementary colors. Complementary colors are pairs of colors that are opposite each other on the color wheel. When placed next to each other, they create a strong contrast that can enhance the vibrancy of each color.

For example, green is the complementary color of red, and purple is the complementary color of yellow. This means that a red gemstone like a ruby can be made to appear even more vibrant when paired with a green gemstone like an emerald.

In addition to complementary colors, the color spectrum can also be used to predict the colors that a gemstone might exhibit. For example, if a gemstone absorbs all of the colors in the spectrum except for green, it will appear green to the human eye. Similarly, if a gemstone absorbs all of the colors except for red, it will appear red.

Popular Gemstones and Their Colors

Now that we understand the connection between the color spectrum and gemstone colors, let's take a closer look at some popular gemstones and their associated colors.

Ruby - Red

Rubies are one of the most well-known and highly prized gemstones. Their deep red color is caused by the presence of chromium within the stone.

Sapphire - Blue

Sapphires are a type of corundum and come in a range of colors. Blue sapphires are the most well-known and get their color from the presence of iron and titanium.

Emerald - Green

Emeralds are a type of beryl and get their distinctive green color from the presence of chromium and vanadium.

Diamond - Color

Diamonds are typically thought of as being completely colorless, but in reality, diamonds can come in a range of colors. The presence of certain impurities within the crystal lattice is what gives diamonds their color. For example, diamonds with a yellow tint typically contain nitrogen impurities, while diamonds with a pink or red tint typically contain traces of boron.

Amethyst - Purple

Amethysts are a type of quartz and get their purple color from the presence of iron impurities within the crystal lattice.

Aquamarine - Blue

Aquamarines are a type of beryl and get their blue color from the presence of iron impurities. The name "aquamarine" actually means "water of the sea" and refers to the stone's beautiful blue-green color.

Garnet - Red

Garnets are a group of minerals that come in a range of colors, but the most well-known variety is red. The red color is caused by the presence of iron within the stone.

Tools used for Determining Gemstone Colour

Determining the color of a gemstone is a crucial part of gemstone identification and evaluation. Gemologists and jewelers use various tools and techniques to accurately determine the color of a gemstone. In this article, we will explore some of the most commonly used tools for determining gemstone color.

Daylight and Incandescent Light

The most basic and accessible tool for determining the color of a gemstone is natural daylight. Daylight provides a full spectrum of colors, which allows for an accurate assessment of the gemstone's color. Incandescent light, which is the light produced by a typical household light bulb, is also commonly used for gemstone evaluation. However, incandescent light has a warmer tone than daylight, which can affect the perceived color of the gemstone.

Gemological Lamps

Gemological lamps are specially designed lamps that produce a range of light wavelengths to help evaluate the color of a gemstone. These lamps often have different light filters or bulbs that mimic various lighting conditions, such as daylight, incandescent light, and fluorescent light. Gemologists use these lamps to evaluate the gemstone's color under different lighting conditions, which can affect the perceived color.

Spectroscope

A spectroscope is a tool that separates white light into its component colors, allowing for an analysis of the gemstone's spectral signature. When light passes through a gemstone, some of the colors are absorbed, while others are transmitted. By analyzing the colors that are transmitted, gemologists can determine the gemstone's chemical composition and identify any impurities that may affect the color.

Colorimeter

A colorimeter is a tool that measures the intensity and hue of a gemstone's color. The colorimeter measures the amount of light that is reflected by the gemstone and compares it to a reference standard. This allows for a precise measurement of the gemstone's color and can be used to ensure consistency in gemstone grading.

Microscope

A microscope is a powerful tool for gemstone evaluation, as it allows for a detailed analysis of the gemstone's color and clarity. Gemologists use microscopes to observe the gemstone's internal structure and any inclusions that may affect the color. Microscopes can also be used to analyze the gemstone's surface color, which can provide valuable information about the gemstone's origin and treatment history.

In conclusion, determining the color of a gemstone is a critical aspect of gemstone evaluation and requires a combination of tools and techniques. Natural daylight, gemological lamps, spectroscopes, colorimeters, and microscopes are all commonly used tools for determining gemstone color. By carefully analyzing the gemstone's color, gemologists and jewelers can accurately assess its value and ensure that it meets the quality standards expected by consumers.

Conclusion

In conclusion, the color spectrum and gemstone colors are intimately connected. The way that light interacts with gemstones determines their color, and the color spectrum can be used to predict and enhance those colors. Gemstones are prized for their beauty and rarity, and their unique colors are a big part of what makes them so valuable. Whether you prefer the deep red of a ruby or the sparkling green of an emerald, there is a gemstone out there for everyone.