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Original photo by Efetova Anna/ Shutterstock
6 Amazing Facts About Purple
Read Time: 5m
Article image
Original photo by Efetova Anna/ Shutterstock

The color purple is many things — a quirk of human biology, a spectral anomaly, and a symbol of power and prestige that stretches back into time immemorial. These six facts explore the amazingly rich, scientifically complicated history of that intriguing mix of blue and red we call purple.

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Close-up of a group of violet coral shells.
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The origins of the word “purple” lie in the ancient Greek porphura, which also means “purple.” However, the word is also a reference to a particular mollusk — a sea snail, to be precise. Known as the purpura mollusk (Stramonita haemastoma), this sea snail and another known as the dye murex (Bolinus brandaris) were the primary means by which the ancient Phoenicians of the Levant developed a purple dye known as Tyrian purple (named after the city of Tyre, where it was manufactured). Starting possibly as far back as the 16th century BCE, Phoenicians (whose name derives from a Greek word for “purple”) derived the dye from dehydrated mucus glands behind the creature’s rectum. Each mollusk yielded extremely limited amounts of dye, requiring a staggering 12,000 mollusks to produce just one gram of the stuff.

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The Color Purple Technically Doesn’t Exist

Aerial view of different shades of purple paint cans.
Credit: Manuta/ iStock

Our eyes perceive color in the visible spectrum due to particular wavelengths: Red is the longest wavelength, at 700 nanometers, whereas violet is the shortest, at 380 nanometers. This is why the invisible wavelengths just below this threshold are known as ultraviolet, or UV rays (and why wavelengths directly above 700 nanometers are known as “infrared”).

The color purple, however, is what physicists call a “nonspectral color,” meaning it isn’t represented by a particular wavelength of light, but is instead a mixture of them as perceived by our brain. While some people use violet and purple interchangeably, the two colors are distinct; violet (which is part of the visible spectrum) has a more bluish hue, whereas purple is more red. The cones in our eyes receive inputs, and our brain uses ratios of these inputs to represent subtleties of color. Purple is therefore a complete construction of our brain, as no wavelength represents the color naturally. But purple isn’t alone — the same can be said for other colors such as black and white, as well as particular hues mixed with grayscale, such as pink and brown.

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Only One National Flag in the World Contains Purple

Flag of Dominica flying against tropical hills at dusk.
Credit: Darryl Brooks/ Alamy Stock Photo

Expert vexillologists (people who study flags) have noticed a strange color conundrum: Only one national flag in the world contains the color purple, and that flag belongs to the small Caribbean island nation of Dominica. The flag, adopted on November 3, 1978, after the country gained independence from Great Britain, features a green field representing the island's forests, accompanied by yellow, white, and black crosses. At its center is a red disk with 10 stars (for the 10 parishes on the island) — all encircling the purple plumage of the sisserou parrot (Amazona imperialis), the country’s national bird. Although Nicaragua and El Salvador do feature rainbows on their flags, purple technically isn’t found in a spectral rainbow (see above), so the flag of Dominica stands alone in its purple splendor.

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Carrots Used to Be Purple

Aerial view of a group of organic purple carrots.
Credit: Mircea Costina/ Shutterstock

Your average supermarket orange carrot originally evolved thanks to the Dutch during the 16th century. But when the cultivated carrot first appeared some 5,000 years ago in Central Asia, it’s thought that they were often a bright purple rather than the orange we know today. An unsupported myth suggests that the Dutch purposefully cultivated orange carrots to honor their national hero William of Orange, but the more likely reason is that the orange-hued varieties tasted better, stained less, and were overall well adapted to the country’s mild, wet climate. Although you’ll likely have to hunt farther afield than your local Piggly Wiggly, some varieties of carrots today still retain the original purple hue.

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In Elizabethan England, It Could Be Illegal To Wear Purple

Her Majesty the Queen's bottom half of her gown showing purple.
Credit: Print Collector/ Hulton Archive via Getty Images

From ancient times until as recently as the 19th century, the color purple was closely associated with royalty — often because they were the only class that could afford such luxury, which was extremely expensive to produce in the days when the color was still made from sea snails. Persian kings and Egyptian rulers wore the illustrious hue, and Julius Caesar similarly donned a purple toga, setting a 1,500-year-long trend for subsequent emperors in Rome and Byzantium.

The color was so intimately tied with the ruling class that the children of kings, queens, and emperors were said to be “born to the purple.” By the 16th century, however, things slowly began to change, as a wealthy merchant class began snatching purple-dyed garments of their own. In 1577, fearing that such lavish spending on “unnecessary foreign wares” could bankrupt the kingdom, Queen Elizabeth I passed sumptuary laws that essentially outlined a strict dress code based on class. Of course, the color purple (and crimson) was reserved for her majesty and her extended royal family, “upon payne to forfett the seid apparel.”

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The First Synthetic Dye Was Purple

An active image of purple dye in the making.
Credit: Tuayai/ iStock

Royals and the super-wealthy might have retained their grip on the color purple if not for an 18-year-old British chemist named William Henry Perkin. In 1856, Perkin failed to create a synthetic form of quinine, a compound used to treat malaria. When cleaning out the brown sludge in his beaker with alcohol, he noticed the mixture from the failed experiment turned a brilliant purple — a color he eventually called “mauveine.” This happy accident was the world’s first synthetic dye, and Perkin quickly discovered that his serendipitous creation was immensely cheaper to produce, and lasted longer, than the naturally occurring alternative. The exclusionary tyranny of royal purple was over, and even Queen Victoria herself soon began wearing garments dyed in the brilliant synthetic purple.