Have you ever marvelled at the stunning colours of gemstones? These natural wonders come in a rainbow of hues, ranging from the warm orange of the citrine to the cool blue of aquamarines. But have you ever wondered how they get their colours? The answer lies in the scientific principles behind the way light interacts with the minerals that make up each gemstone. Each type of gemstone gets its colour from different elements and impurities that are present in the stone. When light enters a gemstone, it interacts with the atomic structure of the mineral and these impurities, causing certain wavelengths of light to be absorbed while others are reflected back to our eyes. This creates the unique colour we see in each gemstone.
Here's a closer look at the science behind the colours of gemstones and how you can use this knowledge to make informed decisions when purchasing gemstones and gemstone-studded jewellery.
Red & Pink Gemstones
Red and pink gemstones, such as rubies and pink sapphires, get their colour from the presence of chromium in the stone. When light enters the stone, it interacts with the chromium atoms and absorbs all colours except for red and pink, which are reflected back to the viewer. The more chromium there is in the stone, the more intense the red or the pink tone.
Yellow & Orange Gemstones
Yellow and orange gemstones, such as yellow sapphires and citrines, get their colour from the presence of iron in the stone. Iron atoms absorb certain wavelengths of light, which makes the stone appear yellow or orange. The intensity of the colour depends on the amount of iron present in the stone.
Blue Gemstones
Blue gemstones, such as blue sapphires and aquamarines, get their colour from the presence of iron and/or titanium in the stone. The interaction of light with these elements causes the stone to absorb all colours except for blue, which is reflected back to the viewer. The exact shade of blue depends on the specific combination of elements in the stone.
Green Gemstones
Green gemstones, such as emeralds and peridots, get their colour from the presence of chromium and/or iron in the stone. The combination of these two elements creates a unique green colour that can vary in intensity depending on the proportions of each element.
Purple & Violet Gemstones
Purple and violet gemstones, such as amethysts, get their colour from the presence of iron and/or manganese in the stone. The combination of these elements causes the stone to absorb certain wavelengths of light, which gives it its distinctive purple or violet hue.
In addition to the elements and impurities present in the stone, the way that light interacts with the stone can also affect its colour. For example, some gemstones exhibit a phenomenon called pleochroism, which means that they appear to change colour when viewed from different angles and lighting conditions. This occurs when the stone is composed of different crystal orientations that absorb and reflect light differently. Another factor that can affect the colour of a gemstone is the way that it is cut. The angle and orientation of the facets can affect the way that light enters and exits the stone, which can either enhance or diminish the stone's colour.
Pleochroism in an Alexandrite when viewed under different lighting conditions
It's important to note that not all gemstones are created equal. The quality of the stone can also affect its colour. For example, a high-quality ruby will have a deep, intense red colour, while a lower-quality ruby may appear more pink or even brownish. When purchasing gemstone jewellery, it's important to consider the quality of the stone as well as its colour.
The different shades of a Ruby - ranging from a light pink to an intense red
Understanding the science behind the colours of gemstones can also help you make informed decisions when it comes to caring for your gemstone jewellery. Exposure to heat, light, and chemicals can all affect the colour and quality of your gemstones. For example, prolonged exposure to sunlight can cause some gemstones to fade or change colour, while exposure to certain chemicals can cause discolouration or damage to the stone.
To keep your gemstone jewellery looking its best, it's important to follow proper care and maintenance guidelines. This includes storing your jewels in a cool, dry place away from direct sunlight, and avoiding contact with chemicals such as hairspray, perfume, and cleaning products. It's also a good idea to have your gemstone jewellery professionally cleaned and inspected on a regular basis to ensure that it stays in top condition.
When it comes to purchasing gemstone jewellery, it's important to choose a reputable retailer that specializes in high-quality gemstones. Look for a retailer that offers a wide variety of stones and settings, and that provides detailed information about the origin and quality of each stone. You may also want to consider working with a gemmologist or other expert to help you select the perfect stone for your needs.
In conclusion, the science behind the colours of gemstones is a fascinating and complex topic that can help you better understand and appreciate these beautiful stones. By understanding the elements and impurities that give each gemstone its unique colour, as well as the factors that can affect its appearance, you can make informed decisions when it comes to purchasing and caring for your gemstone jewellery. Whether you're looking for a fiery red ruby, a brilliant blue sapphire, or any other type of gemstone, knowing the science behind its colour can help you find the perfect stone to add to your collection.
