Meet the Newest Mineral of the Year: Merelaniite

(Inside Science) -- A shiny gray material that forms as teensy round whiskers has been named the 2016 Mineral of the Year by the International Mineralogical Association. The award, announced this June, recognizes a single newly described mineral from the previous year as displaying particularly interesting and outstanding characteristics.

Merelaniite, named in honor of the miners in the Merelani Hills in Tanzania where the first analyzed specimens came from, was chosen from a field of more than 70 new minerals. It lacks the immediately eye-catching qualities of the big, colorful gems that workers toil to unearth in the area’s underground tunnels, but its intricate beauty reveals itself when viewed up close. Under a microscope, merelaniite’s layers look like delicate paper rolled into a scroll, a rare structure in the mineral world.

“It is a wonderful mineral, which, due to the incommensurate character of its crystal structure, possesses unique tubular morphologies of its crystals,” wrote Sergey Krivovichev, a mineralogist

at St. Petersburg State University in Russia and former president of the International Mineralogical Association, in an email to Inside Science.

The mineral came to the attention of scientists when a high school student interning at the Smithsonian Natural History Museum brought in a rock sample with what looked under magnification like tiny black hairs inside its crevices.

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This scanning electron microscope image shows the scroll-like shape of a merelaniite whisker. The whisker is about 10 microns across at its thickest spot -- only slightly wider than a human red blood cell.

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John Jaszczak

It took about five more years, and the expertise of an international team of researchers to gather the evidence necessary to definitively categorize those whisker-like crevice dwellers as a new mineral and to give them the name merelaniite.

The mineral is made primarily of alternating layers of molybdenum disulfide and lead sulfide. The two materials’ atomic structures don’t perfectly match, which likely creates stresses that cause the layers to curve as the mineral grows, said John Jaszczak, a physicist at the Michigan Technological University in Houghton and a member of the team.

While not as showy as Merelani’s gem crystals, the new mineral is really quite beautiful -- especially on the inside, Jaszczak said.

According to Luca Bindi, a geologist at the University of Florence in Italy who joined the team when Jaszczak and his colleagues asked for help analyzing merelaniite’s complex structure, the mineral intrigued him because it combined wonderful aesthetic peculiarities with a surprising combination of chemical and structural features. “Quoting Spock: Fascinating,” he wrote in an email to Inside Science.

The new mineral is described in a paper in the journal Minerals.