Sapphires are one of the ‘Big Three Gemstones’, alongside emeralds and rubies. They’re formed from a mineral called corundum.
They exist in blue, pink, green, yellow, orange, purple, colourless and black. We call sapphires that aren’t blue, black or colourless “fancy sapphires” or “party sapphires”.
The only colour that sapphires do not come in is red. Red corundum is called ruby. It’s another gem variety of the same mineral.
Corundum is extremely hard and durable. Due to this sapphires lend themselves well to jewellery for daily wear, such as engagement rings.
Unusual sapphire variations also exist. Most noteworthy of all, there is the rare and expensive padparadscha sapphire. Star sapphires have a unique light reflection inside the gem.
Read more about these below.
Intensity and shade of sapphire colours
Within corundum crystals there are trace elements that chnage the gem’s colour. Usually iron, chromium, titanium, vanadium, magnesium or copper. For example, chromium is responsible for a pink hue.
If a sapphire is natural, it is not treated with heat or chemicals to change its colour. This means individual gems are unique. Consequently they show variations in hue, shade and intensity.
Sapphires formed naturally under the earth’s crust millions of years ago. Each one is a creation of Mother Nature. No two are exactly the same.
NO worldwide standard for assessing gemstones exists. Therefore we must evaluate each sapphire in its own right.
Just like diamonds, we genrally judge sapphires by their clarity first. This means a lack of marks, cloudiness or blemishes. We also evaluate them by intensity and uniformity of colour.
Gemmologists tend to value intense hues. But instead in jewellery, the choice is a question of personal preference. Some people prefer light pastel tones, while others like bright ones.
When buying sapphire jewellery, most people prefer blue sapphires. Blue toned sapphire colours are caused by the presence of titanium and iron.
Desirable blue sapphire colours range from light blue to black-blue. Generally speaking, medium to medium-dark tones are preferred in jewellery. Non-valuable blue sapphires are too light or grey. Or have marks and blemishes.
How is the colour of blue sapphires assessed? Like all other gems, we look at the hue, saturation and tone of the stone. “Hue” is the main colour of the sapphire. “Saturation” is the vividness. “Tone” refers to the lightness or darkness.
Blue sapphires are found in various shades of their primary hue (blue). But they can exhibit secondary hues (purple, violet or green).
Pink sapphires can range from baby pink to dark fuchsia. All of these shades are accepted in jewellery. As long as the pink sapphire is clear, bright and doesn’t show flaws.
There is a fine line where a pink sapphire crosses over to red, making it a ruby. Or to purple, making it a purple sapphire. Purple sapphires are similar in color to pink sapphires. But they contain vanadium.
The exact colour distinctions between pink, red and purple sapphires have never been officially established. In fact, they’ve been a bone on contention amongst gem experts through the ages! So if you’re buying pink sapphires, it’s up to you to decide which shade you prefer.
Yellow and orange sapphires
Yellow and orange sapphires have iron impurities in them. This is the main cause of their bright, sunny colour. Yellow sapphires that lean towards orange may also contain chromium traces.
Yellow sapphire colour can range from pale lemon yellow to intense tangerine. Some gem experts say the best yellow sapphires have a vivid golden-orange tone. But most jewellery buyers prefer a lighter yellow.
This is due to the immense popularity of yellow diamonds in celebrity engagement rings. Yellow sapphires are an excellent alternative to yellow diamonds. They’re almost as hard and have beautiful colour and sparkle. Yet they’re more affordable.
Sapphire colours ranging from green to green blue or green-yellow are caused by iron, copper and some titanium.
Green sapphires can range from pale olive to dark bottle green. All shades are acceptable as long as there are no marks in the gem.
Most people who buy green gemstone jewellery prefer emeralds. However, green sapphires are actually better suited to jewellery which is worn daily. They’re much harder and more durable than emeralds.
Star sapphires can be blue, pink, black, gray, white, purple or yellow. They can any color except red, which would be a star ruby. They exhibit a characteristic known as “asterism”. This is a star-like light reflection inside the gem.
Some sapphire colors in the star variety are more valued than others. In general pink and blue are considered the best, grey the worst.
However, below you’ll see a beautiful and expensive exception: a star sapphire called the Star of India. It weighs 563.35 carats. It is almost flawless. Most unusually, it has the star asterism displayed on both sides of the stone. It’s kept at the American Museum of Natural History in New York.
White and black sapphire colours
Sapphire colours also come in monochrome tones. The gem industry refers to pure corundum as “colorless sapphire” or “white sapphire”.
Some jewellers use white sapphires as accent stones in jewellery. This is because they are a genuine but affordable alternative to diamonds. Black sapphires are usually opaque grey stones. Due to this, some designers use them instead of onyx.
Padparadscha – king of sapphire colours
We often refer to intense pink-orange sapphires as padparadscha sapphires. The word “paparadscha” refers to a lotus flower. It has an elusive “sunset” colour.
They are very beautiful, but also very expensive. This means they are not usually sold as commercial jewellery.
There is rather a lot of controversy regarding the exact colour of the padparadscha. Below are two samples. Gem experts agree they are real padparadschas.