What Determines the Color of Gemstones?

What Determines the Color of Gemstones?

What Determines the Color of Gemstones?

What Determines the Color of Gemstones?

What Determines the Color of Gemstones? Gemstones are getting popular in the market due to their unique and mesmerizing color. 0. Whether spotlighting themselves in bridal or fashion jewelry or offering astrological benefits, gemstones have been a fascinating art of nature. What describes the gemstone’s beauty at one glance? Of course, it’s their beautiful color. Each gemstone is defined by its distinctive color. Blue sapphire features a blue hue, the lush green color of emerald stone, or the play of colors best reflected by opals; talk about any of these gems; the charm is irresistible. Let’s explore the science behind the existence of these colors.

What Determines the Color of Gemstones?Science and gemstone color: Revealing the chemistry

The array of colored stones is vast, and we will gain insight into each individually.

Sapphires: The Cause of Elegant Blue Color

What Determines the Color of Gemstones? One of the precious stones, sapphires are known for their impressive color shades. Blue is the most common variety of sapphires. Besides this, fancy sapphires exhibiting colors such as pink, peach, green, yellow, and more are also famous. The fascinating colors are admiring, and the science behind them is also more enjoyable. Sapphires have excellent toughness after diamonds and belong to the corundum mineral family.

Corundum, or aluminum oxide mineral, is the hardest substance known after diamond. Corundum is found in igneous, metamorphic, and sedimentary rocks. The structure of the corundum features aluminum ions distributed within the framework of oxygen ions that form a hexagonal pattern. The mesmerizing blue sapphire color is due to intervalence charge transfer.

In general, the color of any gemstone is determined by the trace amount of transition metal ions. In blue sapphire stone, titanium and iron are present in trace amounts. Iron is present in ferric or ferrous ions, whereas titanium is in a plus-four oxidation state. During the inequivalence charge transfer process, when visible light of a specific wavelength strikes the crystal, the electrons from the lower oxidation cation state get excited and transferred to the higher oxidation state.

This energy change gives the stone a characteristic color. For instance, the red photons are absorbed in Neelam stone, and the blue color is reflected. Hence the stone appears blue.

Emeralds: What Causes the Soothing Green Color?

The gem of spring, the emerald stone, is one of the noteworthy gemstones admired by queens, kings, and aristocrats in ancient times. The beautiful green color of the stone is the point of discussion. After all, this is what captivated the noblemen in history. Why is Panna Stone green?

This emerald-green stone is a beryl mineral family member with a beryllium aluminosilicate composition. As mentioned above, the gemstone’s color is due to trace elements or impurities in the crystal. In the case of natural emerald stones, chromium ions are responsible for the green color.

The arrangement of atoms is different in the beryl crystal. The distance between chromium and oxygen atoms is more. Thus, the crystal absorbs the visible light of a longer wavelength which is red. The green light is reflected, lending color to the stone.

Aquamarine: The Cause of Amazing Aqua Blue Hue

What Determines the Color of Gemstones? The refreshing greenish-blue color of the aquamarine stone is connected to calmness and courage. With the soothing color reflecting the subtle natural shade of seawater, the aquamarine stone price is getting a surge.

The value of this beautiful stone depends on its color intensity and carat weight. The color is one factor determining the price of any gemstone. So, what causes the color of the aquamarine gemstone? This beautiful gemstone is also a member of the beryl family, just like an emerald. The translucent aqua color defines the beauty of this mesmerizing gemstone. A trace amount of iron in the beryl crystal lattice brings this aqua color.

Ruby: The Bold Red Hue of Corundum

Ruby, the red variety of corundum, comes from the Latin word ‘ruber,’ which refers to red color. In this red-colored corundum, chromium atoms are replaced by aluminum. The distance between chromium and oxygen atoms in the crystal structure of the ruby stone is short compared to those in emeralds. Thus, the same element in trace amounts lends green to emeralds and red to rubies.

Alexandrite: The Unique Blend of Different Colors

One of the wonders of nature, alexandrite is known for its exclusive color-changing property. This color-changing gemstone is prized for its rarity. The intensity of color change characterizes alexandrite stone price.

The incredible color change of the stone reflects bluish-green in daylight and purple-red in incandescent light. The science behind this striking ‘alexandrite effect’ is the presence of chromium elements.

Two effects are seen, one in daylight and the other in candlelight and incandescent light. Blue and green light remains unabsorbed in visible light or during daytime; thus, alexandrite appears bluish-green. In ‘cool light,’ the chromium ions absorb red light, and other light remains unabsorbed, lending a purple hue to the stone.

Padparadscha Sapphire: The Pretty Pink-Orange Color

One of the most enticing sapphires is the Padparadscha sapphire, famous for its unique pink-orange color. The color of this beautiful gemstone is reminiscent of the lotus flower and hence named so. The stone’s pink color is due to chromium’s presence in the lattice, while the yellow color is due to the presence of iron as a trace element.

The Padmaraga stone features color instability. For instance, if the gemstone is exposed to sunlight, the yellow-to-orange color intensifies, returning to its original color after some time. The colored centers in the crystal absorb light. When the electrons displace from their original position, the gemstone comes into its actual color. The exclusive pink-orange color determines padparadscha sapphire prices.

Five factors determine the gemstone price; among these, ‘color’ is the most defining. In the world of colored gemstones, one will find a broad spectrum of colors. Though each gem comes from a different family of minerals, the primary reason for these alluring colors is the presence of trace elements.

These trace elements may differ for different crystal structures, giving different colors to the stone. Knowing the science behind the cause of these stones’ color is attractive.
As mentioned above, color is the governing factor in defining the beauty and determining the stone’s price. Concerning this, the color and clarity of the gemstones are enhanced. There are various treatments for each gemstone.

To conclude, the chemistry of gemstone colors is happening but far more than simple. The chemical structure of the gemstone lends it its color. Not every gemstone falls in the metal ion transition category. There are artificial methods also that enhance the stone color. These methods involve treatment and enhancements like heat treatment, coating, bleaching, etc.

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