Sometimes I feel like howlite and magnesite have a bit of a bad rap. They’re kind of like the flour of the gemstone world — pretty basic, of no offense to anyone, and able to be turned into all kinds of things that most people think are much more interesting. White howlite and magnesite get dyed and turned into imitation “turquoise,” “sodalite,” “lapis,” and just about any other opaque stone you can imagine.
It’s particularly good at imitating turquoise, to the point that there are standard operating procedures used for telling genuine turquoise from the faked howlite and magnesite stuff.
Unfortunately, that’s what makes it easy to pass off as rare, beautiful white buffalo turquoise to an unwary observer.
When a Turquoise Isn’t a Turquoise
This part might get a little confusing but hear me out: Howlite isn’t the same as white buffalo turquoise. Neither is magnesite. However, white buffalo turquoise also isn’t actually turquoise. For this reason, people prefer the term “white buffalo stone.”
Turquoise is a phosphate of copper and aluminum (CuAl6(PO4)4(OH)8·4H2O). It’s usually a robin’s egg blue to blue green, but can also tend toward a more yellowish green color. Many specimens also exhibit spots, flecks, or spider web-like patterns of black, gray, or brown matrix material.
True turquoise has a pale bluish- or greenish-white streak when subjected to a streak test. It’s also about a 5-6 on the Mohs hardness scale, but it’s a fairly porous stone. Expensive, high-quality specimens are usually at the harder end of the scale, but softer, cheaper specimens are typically stabilized to improve durability. This stone has some other unique physical characteristics, but these are the ones that are most relevant to this subject.
Howlite is a borate mineral, specifically a calcium borosilicate hydroxide (Ca2B5SiO9(OH)5). It’s a white, cream, or pale gray color, with dark gray to black veins that somewhat resemble matrix inclusions in turquoise. Rarely, howlite forms beautiful flowerlike formations of translucent crystals.
Howlite produces a white streak. It’s about a 3.5 on the Mohs scale, so it’s much softer than turquoise.
Magnesite is a magnesium carbonate mineral (MgCO3). It’s typically white, grayish, yellowish, or brownish, with gray veining.
Magnesite produces a white streak. It has a hardness of 3.5-5.0 on the Mohs scale.
White buffalo stone is a calcite mineral, akin to dolomite, with quartz. It’s found near turquoise and forms under similar conditions. The term “white buffalo” is actually a trade name and refers specifically to stones sourced from the Tonopah, Nevada mine owned by the Otteson family. This type of stone is also sometimes sold as white turquoise or sacred buffalo stone.
This stone is a cream to white color with black or brown veins of chert. Some specimens may show faint hints of blue or green from the iron and copper content of the surrounding rock. It’s a pretty soft stone at about 3.5 on the Mohs scale, and also exhibits a white streak.
How Do You Tell Them Apart?
So, we’ve got three white minerals that all exhibit a white streak when you rub them on an unglazed ceramic plate. How do you tell which is which?
It’s not easy, especially since white buffalo stone is pretty rare. The trade name refers to stone that’s found in only one mine in the world, so it’s not like a lot of samples have undergone the kind of testing that would simplify the identification process. (Honestly, I had a hard time even finding images of it because looking for “white buffalo stone” or “white turquoise” tends to return either nothing, or page after page of howlite!) In most cases, you’ll probably have to use a process of elimination.
The most reliable way is to go by hardness. While all of these stones are pretty soft, white buffalo stone is generally the softest.
You can also perform a visual comparison. Howlite and magnesite usually don’t polish up as well as turquoise or white buffalo stone, so they won’t look as shiny.
Magnesite also tends to have more diffuse veining that makes it resemble marble. The veining in howlite and white buffalo stone is more distinct.
If you have a black light, you can look at the stone’s fluorescence. Howlite gives off a sort of brownish yellow color, while magnesite gives off a bluish green.
If you’re willing to invest in a bit of equipment, you may want to pick up a refractometer. Refractive index testing is a reliable way to tell the difference between very similar minerals. Magnesite has a refractive index of 1.509 to 1.700, while howlite is 1.586 to 1.605. Turquoise falls between 1.610 – 1.650, but I have not found any measurements for white buffalo stone itself.
For most people, the easiest way to tell if they’ve duped is the price and location of the stone they’re buying. The cheaper it is, and the farther it is from Nevada, the more likely it is to be howlite or magnesite instead of genuine white buffalo stone. I always recommend that people buy mine- or miner-direct if at all possible, because it reduces the likelihood that you’ll be stuck dealing with unscrupulous middlemen and mislabeled stones.
Marble Crow 
I have a beautiful squash type necklace purchased in Sedona Nevada. The paperwork that came with it says it is rare WHITE TURQUOISE.
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