In gemology, the color of emerald is classified into three components: hue, saturation, and tone. Emeralds display a wide range of colors, varying from yellow to green to blue green, with the primary and most sought-after color being green. Yellow and blue are commonly found as secondary colors in emeralds. This mesmerizing gemstone belongs to the green beryl species.
The ideal emerald colour is achieved when the tone constitutes approximately 75% on a scale where 0% indicates colorlessness, and 100% denotes a black opaque appearance. A clean and smooth color in an emerald result in high saturation and a vivid hue, imbuing the gem with life and brilliance. However, the presence of gray can influence the saturation and appearance of emeralds, altering the normal color intensity. A grayish-green hue, for instance, indicates lower quality in the emerald’s color.
The most desirable emerald colour lies in the bluish green to pure green range, exhibiting bright color saturation and a tone that is not overly dark. Valuable emeralds possess high transparency and display an even distribution of color with no visible color zoning. If the color leans too much towards yellow or blue, the stone is not classified as an emerald but rather as a beryl, which affects its value accordingly. It’s important to note that the green intensity in the best emerald may vary from that of other emeralds.
The captivating emerald colour is attributed to trace elements such as chromium, vanadium, and iron. The presence or absence of each element, along with their relative proportions, determines the precise color of the emerald crystal.
The vibrant green color is the first thing that comes to mind. But what makes this hue so special? And why are emeralds such a popular choice for jewellery? Keep reading to find out more about this iconic gemstone.
The emerald is the head of the beryl family, the green color is given by the small amounts of chrome or vanadium in different proportions, because in the stones we find colors that look like white and transparent stones that have almost no color until emeralds with a dark, bluish, light and yellowish green tone among others. In the same way, the color of the rough stones is not found on all sides or is not distributed in equal proportions in all the stones. For this reason, facetors must observe, analyse and identify where the colour is and what should be the best cut so that the stone contains the greatest facet focus.
“The homogeneously coloured stone is very rare. With an increase of ten diameters, in thin preparations and with green light, it is observed that the marginal coloration of the stones is formed by a series of lines of coloration that are more intense the closer to the side of the emerald.
These series of lines form hexagons inscribed one inside the other in a very regular way, which together form a hexagonal network around a lighter zone that continues towards the interior of the stone, also formed by paler lines, and this is covered by the central one, likewise formed by lines of an even paler coloration and which forms the core of the stone”.
The philosopher and mathematician Rene Descartes created a system by which the coordinates in a Cartesian plane for the faces of the crystals and their respective relationship could be analyzed. This system is what is known as the X axis, the Y axis and the Z axis, which represent the three dimensions of a body in space.
“In the case of crystals of the hexagonal system, among which beryllium is included, it is more convenient to define the three horizontal axes, instead of the two basic fundamental ones. These three horizontal axes reflect the placement or symmetry of the atoms in the beryllium structure. The fundamental shape of the hexagonal system is a honeycomb-like cell (Hexagonal), when the set of all the cells of the structure is well formed, a geometric object called a hexagonal prism is produced.
this beautiful stone can be found all over the world, but some of the finest specimens come from Colombia. If you’re lucky enough to own an green bluewish stone, make sure to take care of it so that it will stay looking its best for years to come.