Discover the surprising reason behind the colorful natural phenomenon of purple sand
If you’ve ever been to Bermuda, you’ve probably seen their famous pink-sand beaches, made up of the shells of tiny sea creatures. Or if you’ve traveled to Hawaii, you may have visited black-sand beaches, created from dark volcanic lava rock. But have you ever seen a beach made of purple sand? It’s something you’ll never forget.
Several ocean and lake beaches in North America experience this purple phenomenon. But what causes these beautiful colored-sand beaches to form in the first place? We asked Peter Adams, a professor in the department of geological sciences at the University of Florida, about the scientific explanation for this colorful oddity. Keep reading to find out why these beaches are purple, and where you can experience them for yourself.
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Where are beaches with purple sand located?
You can find purple-sand beaches on both the Pacific and Atlantic coasts of the United States, as well as inland lakes in Canada. Here’s where to go:
Where to see purple-sand beaches in the U.S.
- Big Sur: Pfeiffer Beach, a mile-long beach in Los Padres National Forest, features the Keyhole Arch rock formation in addition to its striking purple sand, making it one of the best beaches in California.
- Plum Island: Ironically, this 8-mile long barrier island on Massachusetts’s North Shore isn’t named for the hue of its purple sand, but rather the beach plum bushes that grow in abundance there.
- Crane Beach: Also in Massachusetts, Crane Beach not only has purple sand, it has a sound phenomenon known as “singing sand,” which results from grains of sand moving against one another.
- Revere Beach: Boston was abuzz in February 2024 when a stretch of beautiful purple sand appeared on this beach just north of the city. Winter storm conditions were just right to reveal the purple deposits of color.
Where to see purple-sand beaches in Canada
- Purple Sands Beach: The most well-known purple-sand beach in Canada can be seen along the shores of remote Candle Lake, in central Saskatchewan.
- Good Spirit Lake: Also in Saskatchewan, this lake offers glimpses of purple sand when the light is right.
- Clearwater Lake: In the neighboring province of Manitoba, this is one of the most crystal-clear lakes you’ll ever see, as its name implies—but it also has “secret” purple-sand beaches along its north and east shores.
What is purple sand made of?
Purple sand consists of deposits of the mineral garnet. “Garnets tend to be resistant to weathering, which may explain why it is so notable at places like Pfeiffer Beach—it is durable, so it can grow in concentration over time, even if its input is slow and in small concentrations,” Adams says.
In contrast, most “regular” sand that’s tan in color is made of commonly occurring quartz, Adams says.
Adams suspects that at Pfeiffer Beach, the specific garnet is Spessartine, which is a type of garnet whose chemical composition contains the element manganese and the rock-forming element silicon.
“Spessartine is approximately 1.5 times denser that quartz sand, which means it will require greater shear stress to entrain and transport,” Adams says. He goes on to explain that it’s likely this beach has current conditions and swash (the movement of waves on the sand) “that are sufficient to move the ‘regular’ quartz sand, but insufficient to get the Spessartine mobilized.” In other words, the waves can only move the lighter regular sand, leaving the purple sand behind.
Why do some beaches have purple sand?
It has to do with where and how the garnet was deposited. “Along coasts with sea cliffs and nearby mountainous terrain, landslides and rockfalls routinely contribute material to the beaches,” Adams says. This is the case with Pfeiffer Beach, whose treacherous sea cliffs and strong currents make it one of the most dangerous beaches—but also one of the most stunning.
“Along the Big Sur coast, the sea cliffs are composed of metamorphic rocks that have been altered by extreme temperatures and pressures, which commonly create metamorphic minerals such as garnets,” Adams says. “Because this sediment source is nearby, it’s not surprising the Spessartine is found in higher concentrations at this beach.”
In the case of Saskatchewan, that area of Canada is rich in minerals, including garnet, which may have been picked up by huge sheets of ice during the last Ice Age and eventually deposited on the lake shores.
The northern Massachusetts beaches may have received garnet deposits from rivers flowing from the White Mountains of New Hampshire. “Along all coasts, rivers supply sediment to the coastal ocean,” Adams says.
Why are some purple-sand beaches different shades?
This is due to the specific way the garnet was formed, and whether the sand is mixed with other minerals. For example, the garnet at Plum Island is likely mixed with rose quartz. These differences can result in tints ranging from light lavender to bright magenta and everything in between.
“There may be different hues of purple that owe their origin to the specific conditions operating when the metamorphism was taking place,” Adams says. “The metamorphism in Saskatchewan may’ve seen different temperature and pressure conditions, resulting in a different mineralogic product.”
Is it safe to swim when you see purple sand?
Yes, it’s perfectly safe to swim at beaches with purple sand, as the garnet isn’t harmful. “To my knowledge, there’s no reason that swimming would be unsafe along beaches with Spessartine,” Adams says.
Is the purple sand more prevalent at a certain time?
Some beaches may regularly display their purple color, but at others it may depend on the time of year, the light, the current, the weather or a combination. In February 2024 at Revere Beach, for example, a winter storm that moved in a different direction than usual uncovered the swaths of garnet. At Pfeiffer Beach, the purple color is especially visible after rain.
The purple may also become more noticeable during high winds or other environmental circumstances, or during low tide after the waves have exposed new sediment on the beach. “If certain tidal and wave conditions create a swash current of the strength sufficient to move quartz, but insufficient to move the garnet, it could concentrate these heavy minerals and enhance the purple appearance of the beach,” Adams says.
In Saskatchewan, most people see the purple sand in the summer, which could be because in winter the lake is frozen and the sand is covered in snow!
It can be difficult to know exactly when you’re most likely to see purple sand, but checking out these beaches at low tide, and after storms or other weather events, may be your best bet.
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Sources:
- Peter N. Adams, PhD, professor in the department of geological sciences at the University of Florida; email interview, September 2025
- BBC: “Canada’s little-known geological wonder”
- JEOL: “Why Is the Sand Purple at Plum Island Beach?”
- Geomorphology: “Quantitative regional observations of gravel and bedrock influence on beach morphologies”
- National Park Service: “Coastal Geomorphology”
- Clearwater Lake Provincial Park: “Management Plan”
- USDA Forest Service: “Pfeiffer Beach Day Use”
- WCVB Channel 5 Boston: “Sand at Mass. beach turns purple; Here’s Why”
- WMUR-TV: “Purple sand seen at northern Mass. beaches”
- Islands: “The Popular and Beautiful Massachusetts Beach Famous for Its Strange ‘Singing’ Quality”
- Saskatchewan Parks: “Good Spirit Lake Provincial Park”
