Coloured stones or Gemstones are prized for centuries for their rarity and revered for their rainbow of hues, which have long rivaled diamonds as the world’s greatest natural treasures. These coloured stones have long enjoyed a vast history that illuminates their importance and a wide variety of uses. Tanzanite, Topaz, Tourmaline, Ruby, Sapphire, Emerald, Pink Quartz stones, etc. – the list is endless.
Every gemstone is unique with its own aesthetic appeal with its colour, symmetry, and surface appearance. The greatest source of a gem’s beauty and allure has always been its colour. Clear, crystalline, and sharp, coloured stones/diamonds are known for their hardness. This article dives you into the wonderful world of stones colours and gems in India.
Understanding Colour and Phenomena
The colour that an observer sees in a gemstone is born from an interaction between light, the gemstone, and the observer. Light, although seemingly white, is a combination of all the colours of the spectrum, and each colour represents different energies. Because of these different energies, some light waves are absorbed more fully by the coloured stones or gemstones through a process called selective absorption. These colored stones are used for decoration, for jewellery like colored stones rings and necklaces. Importantly, it’s the light waves that aren’t absorbed – in other words, returned – that determine the colour the observer sees. It is the gem’s chemical composition and crystal structure that ultimately affects the way it absorbs and returns light.
Three key terms are most commonly used when identifying and describing coloured gemstones: hue, tone, and saturation. While discussing colour, start with describing your first impression of the gemstone’s basic body colour—the hue of the gemstone. Next, delve into the specifics of that basic colour, including its relative degree of darkness or lightness. This is known as the stone’s tone, which helps specify the specific stone in question. Finally, note how strong or light the stone’s colour appears. This is its saturation. Highly saturated coloured gemstones, such as Bubblegum Pink Sapphires, will often appear vivid and intense.
Oftentimes, many in the gemstone sphere immediately give Carat, one of the 4 Cs, priority over the remaining three Cs: Cut, Colour, and Clarity. This is because many people think bigger is better, and as carat refers to the weight by which gemstones, as well as diamonds, are measured, it just has to be the most important factor.
Cut – Modern gems or coloured stones are most often cut with a top and bottom, or as the industry calls it, the crown and the pavilion. Antique gems will have a much flatter pavilion than will gems cut in the last decades.
How the pavilion is cut affects how light is reflected back to the observer. The better the cut on the pavilion, the more fire and sparkle, and the more valuable it. Most modern gems, especially diamonds – have what is called a Brilliant Cut in which the facets are cut to reflect the most light back up through the crown. Cut also refers to the shape of the stone. Coloured stones come in a wonderful variety of shapes including:
Colour – Diamonds and other precious gemstones are graded on their colour. The Gemological Institute of America has a standard grading system for determining the colour, and thereby the value of gemstones. Diamonds are graded D-Z, with “D” being the most white and “Z” the most yellow.
Clarity – Clarity makes a great deal of difference in value. Fractures, fissures, and imperfections are called inclusions to change the clarity of a coloured gemstone. A flawless diamond or other gemstone has none of these defects visible under close examination. Gemstones are examined for flaws under magnification. Diamonds are graded using the following criteria for a skilled grader using 10× magnification:
- Flawless (FL) – No inclusions or blemishes are visible
- Internally Flawless (IF) – No inclusions and only blemishes are visible
- Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult
- Very Slightly Included (VS1 and VS2) – Inclusions are minor and range from difficult to somewhat easy
- Slightly Included (SI1 and SI2) – Inclusions are noticeable
- Included (I1, I2, and I3) – Inclusions are obvious and may affect transparency and brilliance
Carat Weight – The size of a coloured gemstone as measured by its carat weight has a great bearing on its desirability and value. Larger coloured gemstones/diamonds, are relatively rare and are of greater value, though a larger coloured stone can be worth less than a smaller one depending on other factors, such as cut, clarity, and colour.
Laboratory-grown coloured stones, Imitations, and Disclosure
Until a few years ago, it was still considered the fundamental way, technologically speaking, to be able to make gemstone-quality diamonds in a laboratory. The results are small (under a carat) and industrial-grade—great for use in cutting tools, given the hardness of diamonds, but not high-quality enough for engagement rings.
The machines and processes used to make man-made diamonds have become more refined in recent years, finally able to simulate the extreme pressure and temperatures deep within the Earth’s core that created organic diamonds over billions of years. Today’s lab-grown diamonds are finally of sufficient quality to be certified by third-party institutions, such as the Gemological Institute of America, as real.
What are Lab-created/ Lab-grown Stones?
Simply put, these are diamonds/stones grown in a lab. These labs use cutting-edge technology to replicate the natural processes that create diamonds/coloured gemstones found on the earth. The end result is a lab-created gemstone/diamond that is the same as a mined one chemically, physically, and optically. A lab-created stone is “grown” inside a lab using cutting-edge technology that replicates the natural diamond growing process.
How are coloured stones certified and graded?
Coloured stones are graded and certified using the same process as mined diamonds. They are sent to a gem lab that specializes in grading coloured stones. The majority of these labs grade using the 4C’s, however, a select few use their own criteria. This grading process is roughly the same for all of the coloured stones certification labs. Each coloured stone is graded independently by several gemologists at the lab. The individual grades are compiled and analyzed to determine the final grade. This process is designed to provide each coloured stone with an unbiased grade. However, it’s not uncommon for a stone to get a different grade, not only from a different lab but from the same lab if sent back for a second grading.
Durability, Care, and Cleaning of coloured stones
What do you need to clean your gemstone jewelry? For many pieces, mild detergent, warm water, and a soft brush are a good start. However, before you decide to clean your collection yourself, or even if you leave it to a professional jeweler, add a little gemology to the mix.
Once you’ve identified your gems, consult our gemstone care guide for how to clean your jewelry.
- Most commercially prepared jewelry cleaners are safe but beware of those that contain ammonia/chemicals that can damage sensitive gems.
- Let your jewelry piece soak for a few moments in a solution of warm water and mild detergent/cleaning solution.
- Use a soft brush to gently scrub your jewelry.
- A shaved matchstick or toothpick is quite good at picking out accumulations.
- When you’ve finished scrubbing, dip the jewelry piece back into the solution for one last wetting. Then rinse in warm running water. Radical temperature changes should be avoided.
- Shake or blow on the jewelry piece to remove excess liquid, then gently polish with a soft lint-free cloth.
- Dispense with the cloth and immerse the jewelry piece in a bed of dry maple wood chips. Once dry, blow away the chips.
Presenting the Big 3 coloured stones
When one thinks of colored gemstones, three jewels come to mind first. Rubies, sapphires, and emeralds have been favorites for thousands of years, and continue to be admired. Their place of prominence in the coloured gemstone world is such that they are sometimes referred to as the Big Three. Big 3 coloured gemstone jewelry can be as in demand as some of the finest diamond pieces. These gemstones come in many qualities, sizes, and designs, enough to fit anyone’s tastes and a range of budgets.
In Sanskrit, the name ruby translates to “king of gemstones.” Others are so admired for their colour, carat, or unusual clarity characteristics that they reside in museums or break records at auctions. Unique rubies like these may be considered especially beautiful. Red or slightly purplish red rubies with strong saturation and medium or medium dark tones are highly sought out for their colour. Rubies have among the highest per carat value of coloured gemstones, and fine quality rubies over one carat are rare. In rare instances, rutile aligns within the ruby, creating optical phenomena such as chatoyancy or asterism.
Sapphires are a jewel-quality version of the mineral known as corundum. In its purest state, sapphire is colourless. Many sapphires contain trace elements of iron or titanium, giving the gemstone the blue it’s famed for. Aside from having a blue tint, there are other factors that help make a sapphire its best. While the hue range for blue sapphire runs from violet through blue to very strongly green blue, the most admired hues lean toward blue or violetish blue. They help to determine the jewel’s origin, as well as help to identify individual jewels. Some clarity characteristics help add to a sapphire’s beauty.
Emeralds are one of the most famous members of the beryl family. It’s beloved for its intense greens, to the extent that “emerald” is used as a descriptor for anything verdant. Some versions of the jewel are more likely to turn heads than others. The hue of an emerald is between green and very strongly blue-green, with medium or medium dark tones. Saturation may be strong to vivid, with more intensity preferred. Colouring should be even throughout the stone, without unintentional zoning. Blue-green jewels with medium tone and vivid saturation are often sought out.
To know more about the details of coloured stones or gemstones, keep reading our blog and read more only here. Mintly is the hiring marketplace for the Gems, Jewellery, and precious Metals Industry. Looking for a better career in the industry, try using Mintly.