Friday Fun / Geo-Science: Ho-kwang ("Dave") Mao Predicted This Rare Crystalline Form Of CaSiO3 -- Now It's Been Found.

This particular crystaline form of CaSiO₃, called perovskite, was known to appear in meteorites, but was assumed to lie only deep inside the Earth's mantle (over 600 miles or more deep) as it degrades to other more mundane minerals, if the intense pressure upon it wanes, as a plate lifts toward the surface. [So too with meteorites -- flash-melted by the pressures of entering the atmosphere at over 50,000 mph, and then re-solidifed, in an instant.]

But "Dave" Mao posited that perhaps, somewhere -- rising up from deep below, an ancient diamond shard. . . somewhere, might have encapsulated a calcium silicate perovskite crystal, much as amber has preserved delicate Jurassic era mosquitos and spiders. It turns out, he was -- and is -- right.

So now, from a mine deep under Botswana, but still very near our surface, an ancient diamond was unearthed, that over millions of years, had been a lifted "passenger" upon a plate from the mantle -- over 400 miles below. And so, Dave's "rare bird" has been found, already eternally caged -- inside a diamond (per Science News):

. . .A tiny bit of rock trapped inside a diamond is now opening a brand-new window into what the planet’s lower mantle looks like. Inside the diamond is a newly identified silicate mineral dubbed davemaoite that can only have formed in Earth’s lower mantle, researchers report November 12 in Science. It’s the first time that scientists have managed to definitively prove that this type of lower mantle mineral — previously just predicted from laboratory experiments — actually exists in nature. The team named the mineral for well-known experimental high-pressure geophysicist Ho-kwang (Dave) Mao (SN: 3/16/04).

The diamond bearing the telltale mineral inclusion came from a Botswana mine and formed at depths greater than 660 kilometers, the upper boundary of Earth’s lower mantle. Using analytical techniques including X-ray diffraction, X-ray fluorescence imaging and infrared spectroscopy, mineralogist Oliver Tschauner of the University of Nevada, Las Vegas, and colleagues identified the chemical makeup and structure of the new mineral, pegging it as a type of calcium silicate perovskite. . . .

Now you know. . . onward, into the snow squalls here. . . but ever smiling. Piping hot roasted spaghetti squash with a load of melted butter & garlic. . . and some fresh wilted lemon-spinach, up next. A rare gem still, indeed one "Dante Williams" is, and since 1999, once was -- haunted am I, by waters indeed. . . .

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