Coloured Precious Stones
The most popular category of coloured gemstones are Corundum minerals, which can be found in nature in various colours. Blue coloured Corundum is best known as Sapphire, while as “Rubies” we refer to only colours belonging to the spectrum of red. Corundum gemstones that have different hues of the above, also constitute as Sapphires and are distinguished by their colour (pink sapphire, green sapphire etc). They are the second hardest mineral after diamonds, and are mostly valued depending on the intensity of their colour. Other factors such as clarity and cut can affect the appearance of colour, and therefore their value.
Sapphires are gemstones that mostly exhibit blue colour. The tints of colour may vary from light to deep, dark blue. However, they can also be found in completely different hues, such as pink, yellow, green etc. The vividness and saturation of colour are Sapphires’ primary factors of value.
One of the most valuable and famous Sapphires is the one on Princess Dianna’s engagement ring, now belonging to Kate Middleton.
Rubies are one of the most precious varieties of Corundum, and their colour range lies on the spectrum of red; from vivid pink, to every red hue until deep, profound red. The intensity of the colour red depends on the quantity of chromium present in the gemstone. Not unlike sapphires, vividness and intensity of colour greatly affect their value.
FANCY COLOURED SAPPHIRESWhile different coloured sapphires besides blue and red are evaluated based on the clarity, size, cut and colour intensity, stones that have different colour hues might differ vastly in price due to their rarity.
The orange-pink Padparadscha sapphire holds the first place while following in order are pink, purple, green and lastly yellow sapphires that are the most commonly found natural sapphires.
Following the Conundrum minerals, other popular gemstones are those coming from Beryl crystals. They exhibit significantly less hardness compared to diamonds and sapphires, and are met in nature in the form of long crystals. For that reason, the available styles of cut stones are much more limited. They are relatively fragile and sensitive to corrosive chemicals, and therefore should be treated with caution both in processing and everyday use.
As “Emeralds” we refer to Beryl Crystals that exhibit a bright green colour, or other vivid hues of green. Commonly, inside most naturally formed Emeralds exist visible inclusions, an effect that gemologists call the “inner garden” (jardin) of an emerald. Due to the form of the natural crystals, the dominating shape for an emerald is an octagonal rectangle step cut, also known as the Emerald Cut. Similar to other precious gems, the quality of the cut and the intensity of colour are the main factors that can affect an emerald’s value. However, due to their difference in density, emeralds can appear slightly bigger than diamonds or sapphires of corresponding carat weight.
Aquamarines are named after the word for sea water in latin, and sea colour is exactly what defines them: deep blue, pale blue, azure and turquoise, from intense and saturated, to light, almost transparent hues. Ideally, the most valuable Aquamarine gems are those of vivid, deep or light blue colour.