Have you ever wondered about the source of gemstone colors and names? We all have a favorite gemstone based on a color that means something special to us (possibly a birthstone), but most of us never consider how that color came to be in the stones we love.
It turns out that nature is an amazing chemist, mixing minerals, and using temperature and light to produce unbelievable beauty in stones all around the world. And many you’ll learn about right here.
Obtained via methods such as open-pit, underground, and alluvial mining, gemstones come to us from all around the world, from volcanos, mines, and even rivers and streams, but the source of their captivating beauty goes much deeper.
And although the most sought-after gemstones usually possess a good degree of transparency and vibrancy, rarity, and a well-proportioned cut, the quality of each gemstone is based on more than meets the eye.
Dive deep into the complex world of mineralogy and crystallography to discover their splendid secrets.
Gemstone Colors And Names: Transition Metals
The color of several gemstones originates from the inclusion of what’s known as a transition metal in the stone’s structure. This takes the form of an impurity in what we would see as an otherwise colorless crystal lattice. These inclusions play a significant role in the stone’s makeup, including both its hardness and its color.
Various transition metals react differently in visible light. The result is the stone’s distinctive color. The responsible transition metal within the gemstone is often a chemical portion containing mineral impurities.
A tiny amount of the transition metal is all that’s needed to influence the necessary change in the stone’s complex internal anatomy to result in what we perceive as the beautiful intensity of their different colors.
What Makes Gemstones Original Colors?
Mesmerizing natural stones with their spectacular variation in color and transparency becomes less of a mystery when as we explore the basics of their mineral formation and what makes each gemstone’s distinctive characteristic.
Minerals, substances with a certain chemical structure, originate through processes like crystallization from molten magma, precipitation (rain from liquid), or the replacement of their original composition from other minerals or rocks.
In turn, the minerals’ physical and chemical composition, including color and transparency, are determined by their specific chemical arrangement.
Different minerals absorb different wavelengths of visible light, which possess different ranges of colors — isn’t that fascinating? This leads to the mineral’s unique color we all find so attractive.
Gemstones often demonstrate color variation because of impurities or trace elements within their crystalline structure. This is known as the allochromatic quality of the stone, which describes the influence of impurities within the stone.
Gemstones And Their Colors: The Value Of Impurities
Chromium and vanadium give emeralds their signature green hue; titanium and iron are responsible for the beautiful blue of the sapphire; chromium produces the compelling red flame in the ruby; and one of the most favorite gemstones, the coveted (and famously resilient) diamond, which can range from colorless to tinted, comes from impurities in its carbon framework.
The transparency of the crystal is determined by the crystal lattice arrangement of the tiny components seen with the help of science and powerful lenses. These, too, are the product of impurities in the crystal’s composition.
If the atoms are arranged in a regular pattern, it is likely to be transparent. Alternatively, an irregular arrangement or impurities and defects may lead to opaqueness, or cloudiness, in the crystal’s structure.
Heat can also play a role in a gemstone’s color. Heat-treated minerals can shift a stone’s color from one state to another. This is the case of a gemstone like zoisite, named tanzanite by Tiffany & Company.
Once heated, the mostly brownish stone undergoes a remarkably beautiful color change. Natural (metamorphic) heating, as well as deliberate, intentional heat treatment, can shift the stone’s color to the more alluring blue the stone is famous for.
Another means to revise a gemstone’s color involves manipulating the way the stone reflects light. Adding a mineral like iron can change the color by influencing the way the gemstone refracts the natural light we see reflected from the stone itself.
Our beloved diamonds are the clearest of all and rank among the most popular gemstones. They consist only of pure carbon atoms that are aligned in a specific geometric pattern which allows visible white light to travel through without scattering or being blocked.
This is the amazing nature of the diamond’s unique sparkle. Likewise, quartz, beryl, and topaz get their translucent beauty from the same phenomenon, although the density of the diamond reflects it in a league all of its own.
Opaque, or semi-transparent gemstones, get their coloration from the absorption of certain wavelengths of light or by having impurities or structural defects in their crystal lattice. These gems can have solid-colored appearances, patterns, or markings on the surface. Examples of opaque gemstones are turquoise, jasper, and agate.
Corundum, an aluminum oxide-based mineral, can display a range of hues and transparencies. These depend on the composition of the gemstone and any impurities it contains.
For example, corundum may be red (ruby), blue (sapphire), yellow, pink, or purple; this is due to the presence of chromium (red), titanium, and iron (blue) or iron (yellow) in its complex crystal structure.
Gemstones also exhibit a wonderful range of clarities, from transparent to translucent to opaque.
Translucent gemstones allow some visible light to pass through them but are not completely transparent.
These gemstones include the precious opal and moonstone, both of which exhibit what is often called a play of color in gemstones, during which white light waves travel through the stone’s interior which acts like a prism, producing a wonderful kaleidoscope of colors.
A Play Of Color
The otherwise pure light we see with our naked eyes is actually a series of waves or wavelengths.
In fact, the colors we see in light have their own distinct wavelengths that react differently depending on the nature of the object that the light interacts with (or that is absorbing visible light). As a result, the color of a gemstone is determined by the way light interacts with it.
This is why a red gemstone that absorbs the entire spectrum of visible light except red will appear red itself. By the same phenomenon, gemstones absorbing all visible light will appear black — another fascinating fact.
Gemstone Types By Color
Opaque gemstones contain such a high degree of mineral impurities that no light passes through them, so they appear solid colors. Lapis lazuli, which is one of the most spectacular blue gemstones, is a good example of an opaque stone.
Some gemstones, valued for their colors in combination with their transparency, have special properties, such as being able to change color or emit light when exposed to ultraviolet light. Examples of such gems include alexandrite, opal, quartz, and garnet.
Gemstones Colors And Names
Popular Gemstones Types By Color And Mineral
|Gemstone||Color||Mineral / Element|
|Diamond||Colorless, with other colors based on impurities||Pure Carbon|
|Sapphire||Blue, with other color possibilities||Iron, Titanium|
|Garnet||Red, Green, Yellow, Orange||Iron, Manganese, Aluminum|
|Topaz||Blue, Pink, Brown, Yellow||Iron, Chromium|
|Tourmaline||Green, Pink, Blue, Black, Brown||Iron, Manganese, Chromium, Vanadium|
|Opal||Various||Microscopic silica spheres|
|Turquoise||Blue-green||Copper, Aluminum, Phosphorus|
|Jade||Green, White, Orange, Brown||Actinolite, Tremolite, Nephrite, Jadeite|
More Fascinating Gemstone Facts