What comes to mind when you think about gem hunting? Do you picture speleologists in special gear exploring ancient caves? Or perhaps think about heavyweight mining equipment used by De Beers and other mining companies? Both of these images might be true, but they are only true for those gemstones we can reach.
But today, we’ll set out on a journey to explore the unreachable, something that is almost always hidden from human eyes. Imagine yourself going 125 miles deep underground. Would you see some gemstones there? Most certainly, yes! This layer of earth is full of exotic minerals such as olivines, pyroxenes, and garnets, not to mention the king of stones – its majesty the diamond.
Don’t forget that at such an extreme depth, minerals are faced with extreme conditions: a temperature of 2200℉ and a pressure of 70,000 atmospheres! At a certain point, stone atoms get rearranged as if by a click, forming a different type of crystal lattice. The set of chemical elements may remain the same, but once under such conditions, the mineral can turn into something completely different. The most famous example is how regular carbon transforms into a diamond.
Many diamonds are born at a depth of 125 miles or deeper. The process of diamond formation occurs over millions or even billions of years. Of course, at such a depth, they are completely unmineable (keep in mind that the deepest mine in the world is just 2,5 miles). However, in areas of volcanic activity, diamonds can rise to the surface along with magma. When it solidifies, it forms kimberlite pipes that contain diamond clusters. Then people turn kimberlite pipes into giant quarries of a bizarre cone shape in order to extract these precious stones.
Wadsleyite is an orthorhombic mineral with the chemical formula β-(Mg,Fe)₂SiO₄. It was first synthesized by Ringwood and Major in 1970, who proposed that if the mineral were ever discovered in nature, it should be named in honor of A.D. Wadsley. The mineral was first found naturally in the Peace River meteorite from Alberta, Canada, in 1963.
Now let’s go even deeper. How about descending to 250 miles underground? The pressure here is about two times stronger (140,000 atmospheres), and the temperature is about 2900℉. This is the upper mantle. Here, we would still see some olivines, garnets, and diamonds, but now other minerals are also added to the mix. For instance, majorite, a fascinating extra-hard purple stone. Strictly speaking, this is also a garnet, but only a little more exotic. With increasing depth and pressure, olivines also transform into another mineral – wadsleyite. This material has a deep green color of varying intensity and is incredibly rare. And it looks just like it’s called – like a fragment of an alien spaceship.
Majorite is a mineral named in 1970 by J.V. Smith and B. Mason in honor of Alan Major, from the Department of Geophysics and Geochemistry at the Australian National University, Canberra. Alan Major played a key role in assisting A.E. Ringwood with the high-pressure synthesis of garnet from pyroxene.
And if we dive down even deeper, we will find ringwoodite, a bright blue gemstone that is partially transparent. And it’s only on the surface that it’s very rare. The Earth’s mantle is actually full of it. Remarkably, this mineral is capable of holding water in the structure of its crystal lattice, which can make up to 1.5% of the stone’s mass. If our seismological data is correct, the ringwoodite layer in the mantle contains much more water than all the planet’s oceans combined. If it could somehow be released and rise to the surface, it would cover the earth with a continuous 2625 feet thick layer of water.
Ringwoodite was named in 1969 by R.A. Binns, R.J. Davis, and S.J.B. Reed in honor of Alfred Edward (“Ted”) Ringwood, a renowned geochemist and Professor of Geology at the Australian National University, Canberra. Ringwood predicted the existence of this mineral based on his laboratory studies. It was first identified in the Tenham meteorite in 1969 and is believed to be present in significant quantities within the Earth’s mantle.
Of course, all of these stones can theoretically be used for making jewelry, but they are extremely rare to come by and can only rise to the surface during extraordinary seismologic events, such as volcanic eruptions. But they would not be practical for creating jewelry on a mass scale anyway because of their extreme hardness. You can only dream of wearing them as pieces as no jewelry companies have them on offer, Olertis being no exception. If you’d still like to see some of these stones with your own eyes, it might be a good idea to visit a geological museum, such as the Harvard Mineralogical Museum or others. We hope humanity hasn’t discovered all the types of gems yet, and that in the future, we’ll be able to excite you with more fascinating stones unearthed by scientists!
