Chemical Composition That Makes Different Color Of Gemstones

Chemical Composition That Makes Different Color Of Gemstone

Certified gemstones are used as jewelry as well as an antidote for astrological issues. There are in all 9 primary gemstones, also known as ‘Navratnas’ in Hindi. These are Ruby, pearl, red coral, emerald, sapphire gemstone, diamond, Hessonite and the cat’s eye.

Each of the gemstones has a ruling planet and the former absorb the ill-effects of the latter. The gemstones also absorb the positive radiations from the planet and bring about the best effects on the wearer. Ruby is governed by Surya or Sun, Pearl is governed by Chandra or Moon, Red coral is governed by the planet Mars, Emerald by Mercury, Yellow Sapphire by Brihaspati, Diamond by Venus, Blue Sapphire by Saturn, Hessonite by the ascending lunar node, cat’s eye by the descending lunar node.

How Do We Perceive Color?

The color perceived depends on the light the object is viewed under. The effect of illumination type can be very important, which is fluorescent versus incandescent light. It must be mentioned here that the eyes are most sensitive to green light. We see radiation with wavelengths in the visible spectrum, which include red, orange, yellow, green, blue, indigo, violet.

Things appear to be of a particular color because some of the processes remove a few wavelengths of the visible spectrum. For instance, a blue sapphire looks black in front of candle light. Candlelight is rich in red wavelength and poor in blue wavelength. Thus, the wavelength of visible light available are exactly those that cannot be transmitted. Therefore, no light is transmitted and the stone appears black.

Why Do Minerals Have Color?

The Color of the minerals is caused due to the presence of different impurities like Ti, V, Cr, Mn, Fe, Ni, Cu. It must be noted here that they are not present in the pure compound. Impurities are present on low intensity in gemstone, thus giving them the desired color. When the impurities are in combined state, they exude unique colors.

It must also be mentioned here that the oxidation state also changes the color. If impurity ions produce color, the color can still be changed if the oxidation state is changed. The same impurities color different gems differently. For instance, Chromium in ruby is red, Chromium in beryl is emerald green and chromium in alexandrite is purplish or red.

This is because Chromium absorbs light differently when it is in beryl, emerald and alexandrite.

Transfer of Charge Also Changes The Color Of Gemstones

Transfer of charge is only possible in compounds that have at least two elements in different and variable oxidation states. Charge transfers can produce very different colors in gems and minerals.

Charge transfer refers to the transfer of electrons when heated. Some of the elements that can participate in charge transfer include Fe2+ and Fe3+; Ti3+ and Ti4+; Mn 2+ and Mn3+ and Mn4+. To add to it, a crystal can contain a mixture of these elements, which can again participate in charge transfers. So, basically energy is transferred from visible light to transfer electrons from one atom to another.

Color of Gems And How They Get It

Ruby gemstone gets its red color when CR3+ replaces Al3+in octahedral sites

• Emerald gets its green color when CR3+ replaces Al3+ in octahedral sites

• Garnet gets its red color when Fe2+ replaces Mg2+ in 8-coordinate set

• Sapphire gets its Blue color due to inter valence transition between FE2+ and Ti4+ replaces Mg 2+ in 6-coordinate set

Why Do Things Look Colored?

Things are colored because some process removes some wavelengths from the visible spectrum. For instance, blue sapphire is blue because this is the only wavelength range of visible light. Candlelight is rich in red wavelength and poor in blue wavelength.

The science of gemstone is unique and complicated and also needs expert gemologists to study the same. In fact, a few jewelers can also tell you what exactly goes behind in the making of a gemstone naturally and synthetically. You can buy original gemstone online, but if you want to know more about them, speak to a jeweler first and understand the beauty of the stones and appreciate their value.

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